Symaptic: os/persistentdata/persistentstorage/sql/SQLite364/select.c@260cb5ec6c19 (annotated)

sl@0	1	/*
sl@0	2	** 2001 September 15
sl@0	3	**
sl@0	4	** The author disclaims copyright to this source code. In place of
sl@0	5	** a legal notice, here is a blessing:
sl@0	6	**
sl@0	7	** May you do good and not evil.
sl@0	8	** May you find forgiveness for yourself and forgive others.
sl@0	9	** May you share freely, never taking more than you give.
sl@0	10	**
sl@0	11	*************************************************************************
sl@0	12	** This file contains C code routines that are called by the parser
sl@0	13	** to handle SELECT statements in SQLite.
sl@0	14	**
sl@0	15	** $Id: select.c,v 1.480 2008/10/07 19:53:14 drh Exp $
sl@0	16	*/
sl@0	17	#include "sqliteInt.h"
sl@0	18
sl@0	19
sl@0	20	/*
sl@0	21	** Delete all the content of a Select structure but do not deallocate
sl@0	22	** the select structure itself.
sl@0	23	*/
sl@0	24	static void clearSelect(sqlite3 db, Select p){
sl@0	25	sqlite3ExprListDelete(db, p->pEList);
sl@0	26	sqlite3SrcListDelete(db, p->pSrc);
sl@0	27	sqlite3ExprDelete(db, p->pWhere);
sl@0	28	sqlite3ExprListDelete(db, p->pGroupBy);
sl@0	29	sqlite3ExprDelete(db, p->pHaving);
sl@0	30	sqlite3ExprListDelete(db, p->pOrderBy);
sl@0	31	sqlite3SelectDelete(db, p->pPrior);
sl@0	32	sqlite3ExprDelete(db, p->pLimit);
sl@0	33	sqlite3ExprDelete(db, p->pOffset);
sl@0	34	}
sl@0	35
sl@0	36	/*
sl@0	37	** Initialize a SelectDest structure.
sl@0	38	*/
sl@0	39	void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
sl@0	40	pDest->eDest = eDest;
sl@0	41	pDest->iParm = iParm;
sl@0	42	pDest->affinity = 0;
sl@0	43	pDest->iMem = 0;
sl@0	44	pDest->nMem = 0;
sl@0	45	}
sl@0	46
sl@0	47
sl@0	48	/*
sl@0	49	** Allocate a new Select structure and return a pointer to that
sl@0	50	** structure.
sl@0	51	*/
sl@0	52	Select *sqlite3SelectNew(
sl@0	53	Parse pParse, / Parsing context */
sl@0	54	ExprList pEList, / which columns to include in the result */
sl@0	55	SrcList pSrc, / the FROM clause -- which tables to scan */
sl@0	56	Expr pWhere, / the WHERE clause */
sl@0	57	ExprList pGroupBy, / the GROUP BY clause */
sl@0	58	Expr pHaving, / the HAVING clause */
sl@0	59	ExprList pOrderBy, / the ORDER BY clause */
sl@0	60	int isDistinct, /* true if the DISTINCT keyword is present */
sl@0	61	Expr pLimit, / LIMIT value. NULL means not used */
sl@0	62	Expr pOffset / OFFSET value. NULL means no offset */
sl@0	63	){
sl@0	64	Select *pNew;
sl@0	65	Select standin;
sl@0	66	sqlite3 *db = pParse->db;
sl@0	67	pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
sl@0	68	assert( !pOffset \|\| pLimit ); /* Can't have OFFSET without LIMIT. */
sl@0	69	if( pNew==0 ){
sl@0	70	pNew = &standin;
sl@0	71	memset(pNew, 0, sizeof(*pNew));
sl@0	72	}
sl@0	73	if( pEList==0 ){
sl@0	74	pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0,0,0), 0);
sl@0	75	}
sl@0	76	pNew->pEList = pEList;
sl@0	77	pNew->pSrc = pSrc;
sl@0	78	pNew->pWhere = pWhere;
sl@0	79	pNew->pGroupBy = pGroupBy;
sl@0	80	pNew->pHaving = pHaving;
sl@0	81	pNew->pOrderBy = pOrderBy;
sl@0	82	pNew->selFlags = isDistinct ? SF_Distinct : 0;
sl@0	83	pNew->op = TK_SELECT;
sl@0	84	pNew->pLimit = pLimit;
sl@0	85	pNew->pOffset = pOffset;
sl@0	86	pNew->addrOpenEphm[0] = -1;
sl@0	87	pNew->addrOpenEphm[1] = -1;
sl@0	88	pNew->addrOpenEphm[2] = -1;
sl@0	89	if( db->mallocFailed ) {
sl@0	90	clearSelect(db, pNew);
sl@0	91	if( pNew!=&standin ) sqlite3DbFree(db, pNew);
sl@0	92	pNew = 0;
sl@0	93	}
sl@0	94	return pNew;
sl@0	95	}
sl@0	96
sl@0	97	/*
sl@0	98	** Delete the given Select structure and all of its substructures.
sl@0	99	*/
sl@0	100	void sqlite3SelectDelete(sqlite3 db, Select p){
sl@0	101	if( p ){
sl@0	102	clearSelect(db, p);
sl@0	103	sqlite3DbFree(db, p);
sl@0	104	}
sl@0	105	}
sl@0	106
sl@0	107	/*
sl@0	108	** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
sl@0	109	** type of join. Return an integer constant that expresses that type
sl@0	110	** in terms of the following bit values:
sl@0	111	**
sl@0	112	** JT_INNER
sl@0	113	** JT_CROSS
sl@0	114	** JT_OUTER
sl@0	115	** JT_NATURAL
sl@0	116	** JT_LEFT
sl@0	117	** JT_RIGHT
sl@0	118	**
sl@0	119	** A full outer join is the combination of JT_LEFT and JT_RIGHT.
sl@0	120	**
sl@0	121	** If an illegal or unsupported join type is seen, then still return
sl@0	122	** a join type, but put an error in the pParse structure.
sl@0	123	*/
sl@0	124	int sqlite3JoinType(Parse pParse, Token pA, Token pB, Token pC){
sl@0	125	int jointype = 0;
sl@0	126	Token *apAll[3];
sl@0	127	Token *p;
sl@0	128	static const struct {
sl@0	129	const char zKeyword[8];
sl@0	130	u8 nChar;
sl@0	131	u8 code;
sl@0	132	} keywords[] = {
sl@0	133	{ "natural", 7, JT_NATURAL },
sl@0	134	{ "left", 4, JT_LEFT\|JT_OUTER },
sl@0	135	{ "right", 5, JT_RIGHT\|JT_OUTER },
sl@0	136	{ "full", 4, JT_LEFT\|JT_RIGHT\|JT_OUTER },
sl@0	137	{ "outer", 5, JT_OUTER },
sl@0	138	{ "inner", 5, JT_INNER },
sl@0	139	{ "cross", 5, JT_INNER\|JT_CROSS },
sl@0	140	};
sl@0	141	int i, j;
sl@0	142	apAll[0] = pA;
sl@0	143	apAll[1] = pB;
sl@0	144	apAll[2] = pC;
sl@0	145	for(i=0; i<3 && apAll[i]; i++){
sl@0	146	p = apAll[i];
sl@0	147	for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
sl@0	148	if( p->n==keywords[j].nChar
sl@0	149	&& sqlite3StrNICmp((char*)p->z, keywords[j].zKeyword, p->n)==0 ){
sl@0	150	jointype \|= keywords[j].code;
sl@0	151	break;
sl@0	152	}
sl@0	153	}
sl@0	154	if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
sl@0	155	jointype \|= JT_ERROR;
sl@0	156	break;
sl@0	157	}
sl@0	158	}
sl@0	159	if(
sl@0	160	(jointype & (JT_INNER\|JT_OUTER))==(JT_INNER\|JT_OUTER) \|\|
sl@0	161	(jointype & JT_ERROR)!=0
sl@0	162	){
sl@0	163	const char *zSp = " ";
sl@0	164	assert( pB!=0 );
sl@0	165	if( pC==0 ){ zSp++; }
sl@0	166	sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
sl@0	167	"%T %T%s%T", pA, pB, zSp, pC);
sl@0	168	jointype = JT_INNER;
sl@0	169	}else if( jointype & JT_RIGHT ){
sl@0	170	sqlite3ErrorMsg(pParse,
sl@0	171	"RIGHT and FULL OUTER JOINs are not currently supported");
sl@0	172	jointype = JT_INNER;
sl@0	173	}
sl@0	174	return jointype;
sl@0	175	}
sl@0	176
sl@0	177	/*
sl@0	178	** Return the index of a column in a table. Return -1 if the column
sl@0	179	** is not contained in the table.
sl@0	180	*/
sl@0	181	static int columnIndex(Table pTab, const char zCol){
sl@0	182	int i;
sl@0	183	for(i=0; i<pTab->nCol; i++){
sl@0	184	if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
sl@0	185	}
sl@0	186	return -1;
sl@0	187	}
sl@0	188
sl@0	189	/*
sl@0	190	** Set the value of a token to a '\000'-terminated string.
sl@0	191	*/
sl@0	192	static void setToken(Token p, const char z){
sl@0	193	p->z = (u8*)z;
sl@0	194	p->n = z ? strlen(z) : 0;
sl@0	195	p->dyn = 0;
sl@0	196	}
sl@0	197
sl@0	198	/*
sl@0	199	** Set the token to the double-quoted and escaped version of the string pointed
sl@0	200	** to by z. For example;
sl@0	201	**
sl@0	202	** {a"bc} -> {"a""bc"}
sl@0	203	*/
sl@0	204	static void setQuotedToken(Parse pParse, Token p, const char *z){
sl@0	205
sl@0	206	/* Check if the string appears to be quoted using "..." or `...`
sl@0	207	** or [...] or '...' or if the string contains any " characters.
sl@0	208	** If it does, then record a version of the string with the special
sl@0	209	** characters escaped.
sl@0	210	*/
sl@0	211	const char *z2 = z;
sl@0	212	if( z2!='[' && z2!='`' && *z2!='\'' ){
sl@0	213	while( *z2 ){
sl@0	214	if( *z2=='"' ) break;
sl@0	215	z2++;
sl@0	216	}
sl@0	217	}
sl@0	218
sl@0	219	if( *z2 ){
sl@0	220	/* String contains " characters - copy and quote the string. */
sl@0	221	p->z = (u8 *)sqlite3MPrintf(pParse->db, "\"%w\"", z);
sl@0	222	if( p->z ){
sl@0	223	p->n = strlen((char *)p->z);
sl@0	224	p->dyn = 1;
sl@0	225	}
sl@0	226	}else{
sl@0	227	/* String contains no " characters - copy the pointer. */
sl@0	228	p->z = (u8*)z;
sl@0	229	p->n = (z2 - z);
sl@0	230	p->dyn = 0;
sl@0	231	}
sl@0	232	}
sl@0	233
sl@0	234	/*
sl@0	235	** Create an expression node for an identifier with the name of zName
sl@0	236	*/
sl@0	237	Expr sqlite3CreateIdExpr(Parse pParse, const char *zName){
sl@0	238	Token dummy;
sl@0	239	setToken(&dummy, zName);
sl@0	240	return sqlite3PExpr(pParse, TK_ID, 0, 0, &dummy);
sl@0	241	}
sl@0	242
sl@0	243	/*
sl@0	244	** Add a term to the WHERE expression in *ppExpr that requires the
sl@0	245	** zCol column to be equal in the two tables pTab1 and pTab2.
sl@0	246	*/
sl@0	247	static void addWhereTerm(
sl@0	248	Parse pParse, / Parsing context */
sl@0	249	const char zCol, / Name of the column */
sl@0	250	const Table pTab1, / First table */
sl@0	251	const char zAlias1, / Alias for first table. May be NULL */
sl@0	252	const Table pTab2, / Second table */
sl@0	253	const char zAlias2, / Alias for second table. May be NULL */
sl@0	254	int iRightJoinTable, /* VDBE cursor for the right table */
sl@0	255	Expr *ppExpr, / Add the equality term to this expression */
sl@0	256	int isOuterJoin /* True if dealing with an OUTER join */
sl@0	257	){
sl@0	258	Expr pE1a, pE1b, *pE1c;
sl@0	259	Expr pE2a, pE2b, *pE2c;
sl@0	260	Expr *pE;
sl@0	261
sl@0	262	pE1a = sqlite3CreateIdExpr(pParse, zCol);
sl@0	263	pE2a = sqlite3CreateIdExpr(pParse, zCol);
sl@0	264	if( zAlias1==0 ){
sl@0	265	zAlias1 = pTab1->zName;
sl@0	266	}
sl@0	267	pE1b = sqlite3CreateIdExpr(pParse, zAlias1);
sl@0	268	if( zAlias2==0 ){
sl@0	269	zAlias2 = pTab2->zName;
sl@0	270	}
sl@0	271	pE2b = sqlite3CreateIdExpr(pParse, zAlias2);
sl@0	272	pE1c = sqlite3PExpr(pParse, TK_DOT, pE1b, pE1a, 0);
sl@0	273	pE2c = sqlite3PExpr(pParse, TK_DOT, pE2b, pE2a, 0);
sl@0	274	pE = sqlite3PExpr(pParse, TK_EQ, pE1c, pE2c, 0);
sl@0	275	if( pE && isOuterJoin ){
sl@0	276	ExprSetProperty(pE, EP_FromJoin);
sl@0	277	pE->iRightJoinTable = iRightJoinTable;
sl@0	278	}
sl@0	279	ppExpr = sqlite3ExprAnd(pParse->db,ppExpr, pE);
sl@0	280	}
sl@0	281
sl@0	282	/*
sl@0	283	** Set the EP_FromJoin property on all terms of the given expression.
sl@0	284	** And set the Expr.iRightJoinTable to iTable for every term in the
sl@0	285	** expression.
sl@0	286	**
sl@0	287	** The EP_FromJoin property is used on terms of an expression to tell
sl@0	288	** the LEFT OUTER JOIN processing logic that this term is part of the
sl@0	289	** join restriction specified in the ON or USING clause and not a part
sl@0	290	** of the more general WHERE clause. These terms are moved over to the
sl@0	291	** WHERE clause during join processing but we need to remember that they
sl@0	292	** originated in the ON or USING clause.
sl@0	293	**
sl@0	294	** The Expr.iRightJoinTable tells the WHERE clause processing that the
sl@0	295	** expression depends on table iRightJoinTable even if that table is not
sl@0	296	** explicitly mentioned in the expression. That information is needed
sl@0	297	** for cases like this:
sl@0	298	**
sl@0	299	** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
sl@0	300	**
sl@0	301	** The where clause needs to defer the handling of the t1.x=5
sl@0	302	** term until after the t2 loop of the join. In that way, a
sl@0	303	** NULL t2 row will be inserted whenever t1.x!=5. If we do not
sl@0	304	** defer the handling of t1.x=5, it will be processed immediately
sl@0	305	** after the t1 loop and rows with t1.x!=5 will never appear in
sl@0	306	** the output, which is incorrect.
sl@0	307	*/
sl@0	308	static void setJoinExpr(Expr *p, int iTable){
sl@0	309	while( p ){
sl@0	310	ExprSetProperty(p, EP_FromJoin);
sl@0	311	p->iRightJoinTable = iTable;
sl@0	312	setJoinExpr(p->pLeft, iTable);
sl@0	313	p = p->pRight;
sl@0	314	}
sl@0	315	}
sl@0	316
sl@0	317	/*
sl@0	318	** This routine processes the join information for a SELECT statement.
sl@0	319	** ON and USING clauses are converted into extra terms of the WHERE clause.
sl@0	320	** NATURAL joins also create extra WHERE clause terms.
sl@0	321	**
sl@0	322	** The terms of a FROM clause are contained in the Select.pSrc structure.
sl@0	323	** The left most table is the first entry in Select.pSrc. The right-most
sl@0	324	** table is the last entry. The join operator is held in the entry to
sl@0	325	** the left. Thus entry 0 contains the join operator for the join between
sl@0	326	** entries 0 and 1. Any ON or USING clauses associated with the join are
sl@0	327	** also attached to the left entry.
sl@0	328	**
sl@0	329	** This routine returns the number of errors encountered.
sl@0	330	*/
sl@0	331	static int sqliteProcessJoin(Parse pParse, Select p){
sl@0	332	SrcList pSrc; / All tables in the FROM clause */
sl@0	333	int i, j; /* Loop counters */
sl@0	334	struct SrcList_item pLeft; / Left table being joined */
sl@0	335	struct SrcList_item pRight; / Right table being joined */
sl@0	336
sl@0	337	pSrc = p->pSrc;
sl@0	338	pLeft = &pSrc->a[0];
sl@0	339	pRight = &pLeft[1];
sl@0	340	for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
sl@0	341	Table *pLeftTab = pLeft->pTab;
sl@0	342	Table *pRightTab = pRight->pTab;
sl@0	343	int isOuter;
sl@0	344
sl@0	345	if( pLeftTab==0 \|\| pRightTab==0 ) continue;
sl@0	346	isOuter = (pRight->jointype & JT_OUTER)!=0;
sl@0	347
sl@0	348	/* When the NATURAL keyword is present, add WHERE clause terms for
sl@0	349	** every column that the two tables have in common.
sl@0	350	*/
sl@0	351	if( pRight->jointype & JT_NATURAL ){
sl@0	352	if( pRight->pOn \|\| pRight->pUsing ){
sl@0	353	sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
sl@0	354	"an ON or USING clause", 0);
sl@0	355	return 1;
sl@0	356	}
sl@0	357	for(j=0; j<pLeftTab->nCol; j++){
sl@0	358	char *zName = pLeftTab->aCol[j].zName;
sl@0	359	if( columnIndex(pRightTab, zName)>=0 ){
sl@0	360	addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias,
sl@0	361	pRightTab, pRight->zAlias,
sl@0	362	pRight->iCursor, &p->pWhere, isOuter);
sl@0	363
sl@0	364	}
sl@0	365	}
sl@0	366	}
sl@0	367
sl@0	368	/* Disallow both ON and USING clauses in the same join
sl@0	369	*/
sl@0	370	if( pRight->pOn && pRight->pUsing ){
sl@0	371	sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
sl@0	372	"clauses in the same join");
sl@0	373	return 1;
sl@0	374	}
sl@0	375
sl@0	376	/* Add the ON clause to the end of the WHERE clause, connected by
sl@0	377	** an AND operator.
sl@0	378	*/
sl@0	379	if( pRight->pOn ){
sl@0	380	if( isOuter ) setJoinExpr(pRight->pOn, pRight->iCursor);
sl@0	381	p->pWhere = sqlite3ExprAnd(pParse->db, p->pWhere, pRight->pOn);
sl@0	382	pRight->pOn = 0;
sl@0	383	}
sl@0	384
sl@0	385	/* Create extra terms on the WHERE clause for each column named
sl@0	386	** in the USING clause. Example: If the two tables to be joined are
sl@0	387	** A and B and the USING clause names X, Y, and Z, then add this
sl@0	388	** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
sl@0	389	** Report an error if any column mentioned in the USING clause is
sl@0	390	** not contained in both tables to be joined.
sl@0	391	*/
sl@0	392	if( pRight->pUsing ){
sl@0	393	IdList *pList = pRight->pUsing;
sl@0	394	for(j=0; j<pList->nId; j++){
sl@0	395	char *zName = pList->a[j].zName;
sl@0	396	if( columnIndex(pLeftTab, zName)<0 \|\| columnIndex(pRightTab, zName)<0 ){
sl@0	397	sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
sl@0	398	"not present in both tables", zName);
sl@0	399	return 1;
sl@0	400	}
sl@0	401	addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias,
sl@0	402	pRightTab, pRight->zAlias,
sl@0	403	pRight->iCursor, &p->pWhere, isOuter);
sl@0	404	}
sl@0	405	}
sl@0	406	}
sl@0	407	return 0;
sl@0	408	}
sl@0	409
sl@0	410	/*
sl@0	411	** Insert code into "v" that will push the record on the top of the
sl@0	412	** stack into the sorter.
sl@0	413	*/
sl@0	414	static void pushOntoSorter(
sl@0	415	Parse pParse, / Parser context */
sl@0	416	ExprList pOrderBy, / The ORDER BY clause */
sl@0	417	Select pSelect, / The whole SELECT statement */
sl@0	418	int regData /* Register holding data to be sorted */
sl@0	419	){
sl@0	420	Vdbe *v = pParse->pVdbe;
sl@0	421	int nExpr = pOrderBy->nExpr;
sl@0	422	int regBase = sqlite3GetTempRange(pParse, nExpr+2);
sl@0	423	int regRecord = sqlite3GetTempReg(pParse);
sl@0	424	sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
sl@0	425	sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
sl@0	426	sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
sl@0	427	sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
sl@0	428	sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
sl@0	429	sqlite3ReleaseTempReg(pParse, regRecord);
sl@0	430	sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
sl@0	431	if( pSelect->iLimit ){
sl@0	432	int addr1, addr2;
sl@0	433	int iLimit;
sl@0	434	if( pSelect->iOffset ){
sl@0	435	iLimit = pSelect->iOffset+1;
sl@0	436	}else{
sl@0	437	iLimit = pSelect->iLimit;
sl@0	438	}
sl@0	439	addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit);
sl@0	440	sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
sl@0	441	addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
sl@0	442	sqlite3VdbeJumpHere(v, addr1);
sl@0	443	sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
sl@0	444	sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
sl@0	445	sqlite3VdbeJumpHere(v, addr2);
sl@0	446	pSelect->iLimit = 0;
sl@0	447	}
sl@0	448	}
sl@0	449
sl@0	450	/*
sl@0	451	** Add code to implement the OFFSET
sl@0	452	*/
sl@0	453	static void codeOffset(
sl@0	454	Vdbe v, / Generate code into this VM */
sl@0	455	Select p, / The SELECT statement being coded */
sl@0	456	int iContinue /* Jump here to skip the current record */
sl@0	457	){
sl@0	458	if( p->iOffset && iContinue!=0 ){
sl@0	459	int addr;
sl@0	460	sqlite3VdbeAddOp2(v, OP_AddImm, p->iOffset, -1);
sl@0	461	addr = sqlite3VdbeAddOp1(v, OP_IfNeg, p->iOffset);
sl@0	462	sqlite3VdbeAddOp2(v, OP_Goto, 0, iContinue);
sl@0	463	VdbeComment((v, "skip OFFSET records"));
sl@0	464	sqlite3VdbeJumpHere(v, addr);
sl@0	465	}
sl@0	466	}
sl@0	467
sl@0	468	/*
sl@0	469	** Add code that will check to make sure the N registers starting at iMem
sl@0	470	** form a distinct entry. iTab is a sorting index that holds previously
sl@0	471	** seen combinations of the N values. A new entry is made in iTab
sl@0	472	** if the current N values are new.
sl@0	473	**
sl@0	474	** A jump to addrRepeat is made and the N+1 values are popped from the
sl@0	475	** stack if the top N elements are not distinct.
sl@0	476	*/
sl@0	477	static void codeDistinct(
sl@0	478	Parse pParse, / Parsing and code generating context */
sl@0	479	int iTab, /* A sorting index used to test for distinctness */
sl@0	480	int addrRepeat, /* Jump to here if not distinct */
sl@0	481	int N, /* Number of elements */
sl@0	482	int iMem /* First element */
sl@0	483	){
sl@0	484	Vdbe *v;
sl@0	485	int r1;
sl@0	486
sl@0	487	v = pParse->pVdbe;
sl@0	488	r1 = sqlite3GetTempReg(pParse);
sl@0	489	sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
sl@0	490	sqlite3VdbeAddOp3(v, OP_Found, iTab, addrRepeat, r1);
sl@0	491	sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
sl@0	492	sqlite3ReleaseTempReg(pParse, r1);
sl@0	493	}
sl@0	494
sl@0	495	/*
sl@0	496	** Generate an error message when a SELECT is used within a subexpression
sl@0	497	** (example: "a IN (SELECT * FROM table)") but it has more than 1 result
sl@0	498	** column. We do this in a subroutine because the error occurs in multiple
sl@0	499	** places.
sl@0	500	*/
sl@0	501	static int checkForMultiColumnSelectError(
sl@0	502	Parse pParse, / Parse context. */
sl@0	503	SelectDest pDest, / Destination of SELECT results */
sl@0	504	int nExpr /* Number of result columns returned by SELECT */
sl@0	505	){
sl@0	506	int eDest = pDest->eDest;
sl@0	507	if( nExpr>1 && (eDest==SRT_Mem \|\| eDest==SRT_Set) ){
sl@0	508	sqlite3ErrorMsg(pParse, "only a single result allowed for "
sl@0	509	"a SELECT that is part of an expression");
sl@0	510	return 1;
sl@0	511	}else{
sl@0	512	return 0;
sl@0	513	}
sl@0	514	}
sl@0	515
sl@0	516	/*
sl@0	517	** This routine generates the code for the inside of the inner loop
sl@0	518	** of a SELECT.
sl@0	519	**
sl@0	520	** If srcTab and nColumn are both zero, then the pEList expressions
sl@0	521	** are evaluated in order to get the data for this row. If nColumn>0
sl@0	522	** then data is pulled from srcTab and pEList is used only to get the
sl@0	523	** datatypes for each column.
sl@0	524	*/
sl@0	525	static void selectInnerLoop(
sl@0	526	Parse pParse, / The parser context */
sl@0	527	Select p, / The complete select statement being coded */
sl@0	528	ExprList pEList, / List of values being extracted */
sl@0	529	int srcTab, /* Pull data from this table */
sl@0	530	int nColumn, /* Number of columns in the source table */
sl@0	531	ExprList pOrderBy, / If not NULL, sort results using this key */
sl@0	532	int distinct, /* If >=0, make sure results are distinct */
sl@0	533	SelectDest pDest, / How to dispose of the results */
sl@0	534	int iContinue, /* Jump here to continue with next row */
sl@0	535	int iBreak /* Jump here to break out of the inner loop */
sl@0	536	){
sl@0	537	Vdbe *v = pParse->pVdbe;
sl@0	538	int i;
sl@0	539	int hasDistinct; /* True if the DISTINCT keyword is present */
sl@0	540	int regResult; /* Start of memory holding result set */
sl@0	541	int eDest = pDest->eDest; /* How to dispose of results */
sl@0	542	int iParm = pDest->iParm; /* First argument to disposal method */
sl@0	543	int nResultCol; /* Number of result columns */
sl@0	544
sl@0	545	if( v==0 ) return;
sl@0	546	assert( pEList!=0 );
sl@0	547	hasDistinct = distinct>=0;
sl@0	548	if( pOrderBy==0 && !hasDistinct ){
sl@0	549	codeOffset(v, p, iContinue);
sl@0	550	}
sl@0	551
sl@0	552	/* Pull the requested columns.
sl@0	553	*/
sl@0	554	if( nColumn>0 ){
sl@0	555	nResultCol = nColumn;
sl@0	556	}else{
sl@0	557	nResultCol = pEList->nExpr;
sl@0	558	}
sl@0	559	if( pDest->iMem==0 ){
sl@0	560	pDest->iMem = pParse->nMem+1;
sl@0	561	pDest->nMem = nResultCol;
sl@0	562	pParse->nMem += nResultCol;
sl@0	563	}else if( pDest->nMem!=nResultCol ){
sl@0	564	/* This happens when two SELECTs of a compound SELECT have differing
sl@0	565	** numbers of result columns. The error message will be generated by
sl@0	566	** a higher-level routine. */
sl@0	567	return;
sl@0	568	}
sl@0	569	regResult = pDest->iMem;
sl@0	570	if( nColumn>0 ){
sl@0	571	for(i=0; i<nColumn; i++){
sl@0	572	sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
sl@0	573	}
sl@0	574	}else if( eDest!=SRT_Exists ){
sl@0	575	/* If the destination is an EXISTS(...) expression, the actual
sl@0	576	** values returned by the SELECT are not required.
sl@0	577	*/
sl@0	578	sqlite3ExprCodeExprList(pParse, pEList, regResult, eDest==SRT_Output);
sl@0	579	}
sl@0	580	nColumn = nResultCol;
sl@0	581
sl@0	582	/* If the DISTINCT keyword was present on the SELECT statement
sl@0	583	** and this row has been seen before, then do not make this row
sl@0	584	** part of the result.
sl@0	585	*/
sl@0	586	if( hasDistinct ){
sl@0	587	assert( pEList!=0 );
sl@0	588	assert( pEList->nExpr==nColumn );
sl@0	589	codeDistinct(pParse, distinct, iContinue, nColumn, regResult);
sl@0	590	if( pOrderBy==0 ){
sl@0	591	codeOffset(v, p, iContinue);
sl@0	592	}
sl@0	593	}
sl@0	594
sl@0	595	if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
sl@0	596	return;
sl@0	597	}
sl@0	598
sl@0	599	switch( eDest ){
sl@0	600	/* In this mode, write each query result to the key of the temporary
sl@0	601	** table iParm.
sl@0	602	*/
sl@0	603	#ifndef SQLITE_OMIT_COMPOUND_SELECT
sl@0	604	case SRT_Union: {
sl@0	605	int r1;
sl@0	606	r1 = sqlite3GetTempReg(pParse);
sl@0	607	sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
sl@0	608	sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
sl@0	609	sqlite3ReleaseTempReg(pParse, r1);
sl@0	610	break;
sl@0	611	}
sl@0	612
sl@0	613	/* Construct a record from the query result, but instead of
sl@0	614	** saving that record, use it as a key to delete elements from
sl@0	615	** the temporary table iParm.
sl@0	616	*/
sl@0	617	case SRT_Except: {
sl@0	618	sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nColumn);
sl@0	619	break;
sl@0	620	}
sl@0	621	#endif
sl@0	622
sl@0	623	/* Store the result as data using a unique key.
sl@0	624	*/
sl@0	625	case SRT_Table:
sl@0	626	case SRT_EphemTab: {
sl@0	627	int r1 = sqlite3GetTempReg(pParse);
sl@0	628	sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
sl@0	629	if( pOrderBy ){
sl@0	630	pushOntoSorter(pParse, pOrderBy, p, r1);
sl@0	631	}else{
sl@0	632	int r2 = sqlite3GetTempReg(pParse);
sl@0	633	sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
sl@0	634	sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
sl@0	635	sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
sl@0	636	sqlite3ReleaseTempReg(pParse, r2);
sl@0	637	}
sl@0	638	sqlite3ReleaseTempReg(pParse, r1);
sl@0	639	break;
sl@0	640	}
sl@0	641
sl@0	642	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	643	/* If we are creating a set for an "expr IN (SELECT ...)" construct,
sl@0	644	** then there should be a single item on the stack. Write this
sl@0	645	** item into the set table with bogus data.
sl@0	646	*/
sl@0	647	case SRT_Set: {
sl@0	648	assert( nColumn==1 );
sl@0	649	p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affinity);
sl@0	650	if( pOrderBy ){
sl@0	651	/* At first glance you would think we could optimize out the
sl@0	652	** ORDER BY in this case since the order of entries in the set
sl@0	653	** does not matter. But there might be a LIMIT clause, in which
sl@0	654	** case the order does matter */
sl@0	655	pushOntoSorter(pParse, pOrderBy, p, regResult);
sl@0	656	}else{
sl@0	657	int r1 = sqlite3GetTempReg(pParse);
sl@0	658	sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, 1, r1, &p->affinity, 1);
sl@0	659	sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
sl@0	660	sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
sl@0	661	sqlite3ReleaseTempReg(pParse, r1);
sl@0	662	}
sl@0	663	break;
sl@0	664	}
sl@0	665
sl@0	666	/* If any row exist in the result set, record that fact and abort.
sl@0	667	*/
sl@0	668	case SRT_Exists: {
sl@0	669	sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
sl@0	670	/* The LIMIT clause will terminate the loop for us */
sl@0	671	break;
sl@0	672	}
sl@0	673
sl@0	674	/* If this is a scalar select that is part of an expression, then
sl@0	675	** store the results in the appropriate memory cell and break out
sl@0	676	** of the scan loop.
sl@0	677	*/
sl@0	678	case SRT_Mem: {
sl@0	679	assert( nColumn==1 );
sl@0	680	if( pOrderBy ){
sl@0	681	pushOntoSorter(pParse, pOrderBy, p, regResult);
sl@0	682	}else{
sl@0	683	sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
sl@0	684	/* The LIMIT clause will jump out of the loop for us */
sl@0	685	}
sl@0	686	break;
sl@0	687	}
sl@0	688	#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
sl@0	689
sl@0	690	/* Send the data to the callback function or to a subroutine. In the
sl@0	691	** case of a subroutine, the subroutine itself is responsible for
sl@0	692	** popping the data from the stack.
sl@0	693	*/
sl@0	694	case SRT_Coroutine:
sl@0	695	case SRT_Output: {
sl@0	696	if( pOrderBy ){
sl@0	697	int r1 = sqlite3GetTempReg(pParse);
sl@0	698	sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
sl@0	699	pushOntoSorter(pParse, pOrderBy, p, r1);
sl@0	700	sqlite3ReleaseTempReg(pParse, r1);
sl@0	701	}else if( eDest==SRT_Coroutine ){
sl@0	702	sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
sl@0	703	}else{
sl@0	704	sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
sl@0	705	sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
sl@0	706	}
sl@0	707	break;
sl@0	708	}
sl@0	709
sl@0	710	#if !defined(SQLITE_OMIT_TRIGGER)
sl@0	711	/* Discard the results. This is used for SELECT statements inside
sl@0	712	** the body of a TRIGGER. The purpose of such selects is to call
sl@0	713	** user-defined functions that have side effects. We do not care
sl@0	714	** about the actual results of the select.
sl@0	715	*/
sl@0	716	default: {
sl@0	717	assert( eDest==SRT_Discard );
sl@0	718	break;
sl@0	719	}
sl@0	720	#endif
sl@0	721	}
sl@0	722
sl@0	723	/* Jump to the end of the loop if the LIMIT is reached.
sl@0	724	*/
sl@0	725	if( p->iLimit ){
sl@0	726	assert( pOrderBy==0 ); /* If there is an ORDER BY, the call to
sl@0	727	** pushOntoSorter() would have cleared p->iLimit */
sl@0	728	sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
sl@0	729	sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
sl@0	730	}
sl@0	731	}
sl@0	732
sl@0	733	/*
sl@0	734	** Given an expression list, generate a KeyInfo structure that records
sl@0	735	** the collating sequence for each expression in that expression list.
sl@0	736	**
sl@0	737	** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
sl@0	738	** KeyInfo structure is appropriate for initializing a virtual index to
sl@0	739	** implement that clause. If the ExprList is the result set of a SELECT
sl@0	740	** then the KeyInfo structure is appropriate for initializing a virtual
sl@0	741	** index to implement a DISTINCT test.
sl@0	742	**
sl@0	743	** Space to hold the KeyInfo structure is obtain from malloc. The calling
sl@0	744	** function is responsible for seeing that this structure is eventually
sl@0	745	** freed. Add the KeyInfo structure to the P4 field of an opcode using
sl@0	746	** P4_KEYINFO_HANDOFF is the usual way of dealing with this.
sl@0	747	*/
sl@0	748	static KeyInfo keyInfoFromExprList(Parse pParse, ExprList *pList){
sl@0	749	sqlite3 *db = pParse->db;
sl@0	750	int nExpr;
sl@0	751	KeyInfo *pInfo;
sl@0	752	struct ExprList_item *pItem;
sl@0	753	int i;
sl@0	754
sl@0	755	nExpr = pList->nExpr;
sl@0	756	pInfo = sqlite3DbMallocZero(db, sizeof(pInfo) + nExpr(sizeof(CollSeq*)+1) );
sl@0	757	if( pInfo ){
sl@0	758	pInfo->aSortOrder = (u8*)&pInfo->aColl[nExpr];
sl@0	759	pInfo->nField = nExpr;
sl@0	760	pInfo->enc = ENC(db);
sl@0	761	for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
sl@0	762	CollSeq *pColl;
sl@0	763	pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
sl@0	764	if( !pColl ){
sl@0	765	pColl = db->pDfltColl;
sl@0	766	}
sl@0	767	pInfo->aColl[i] = pColl;
sl@0	768	pInfo->aSortOrder[i] = pItem->sortOrder;
sl@0	769	}
sl@0	770	}
sl@0	771	return pInfo;
sl@0	772	}
sl@0	773
sl@0	774
sl@0	775	/*
sl@0	776	** If the inner loop was generated using a non-null pOrderBy argument,
sl@0	777	** then the results were placed in a sorter. After the loop is terminated
sl@0	778	** we need to run the sorter and output the results. The following
sl@0	779	** routine generates the code needed to do that.
sl@0	780	*/
sl@0	781	static void generateSortTail(
sl@0	782	Parse pParse, / Parsing context */
sl@0	783	Select p, / The SELECT statement */
sl@0	784	Vdbe v, / Generate code into this VDBE */
sl@0	785	int nColumn, /* Number of columns of data */
sl@0	786	SelectDest pDest / Write the sorted results here */
sl@0	787	){
sl@0	788	int brk = sqlite3VdbeMakeLabel(v);
sl@0	789	int cont = sqlite3VdbeMakeLabel(v);
sl@0	790	int addr;
sl@0	791	int iTab;
sl@0	792	int pseudoTab = 0;
sl@0	793	ExprList *pOrderBy = p->pOrderBy;
sl@0	794
sl@0	795	int eDest = pDest->eDest;
sl@0	796	int iParm = pDest->iParm;
sl@0	797
sl@0	798	int regRow;
sl@0	799	int regRowid;
sl@0	800
sl@0	801	iTab = pOrderBy->iECursor;
sl@0	802	if( eDest==SRT_Output \|\| eDest==SRT_Coroutine ){
sl@0	803	pseudoTab = pParse->nTab++;
sl@0	804	sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, nColumn);
sl@0	805	sqlite3VdbeAddOp2(v, OP_OpenPseudo, pseudoTab, eDest==SRT_Output);
sl@0	806	}
sl@0	807	addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, brk);
sl@0	808	codeOffset(v, p, cont);
sl@0	809	regRow = sqlite3GetTempReg(pParse);
sl@0	810	regRowid = sqlite3GetTempReg(pParse);
sl@0	811	sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr + 1, regRow);
sl@0	812	switch( eDest ){
sl@0	813	case SRT_Table:
sl@0	814	case SRT_EphemTab: {
sl@0	815	sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
sl@0	816	sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid);
sl@0	817	sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
sl@0	818	break;
sl@0	819	}
sl@0	820	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	821	case SRT_Set: {
sl@0	822	assert( nColumn==1 );
sl@0	823	sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, 1, regRowid, &p->affinity, 1);
sl@0	824	sqlite3ExprCacheAffinityChange(pParse, regRow, 1);
sl@0	825	sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
sl@0	826	break;
sl@0	827	}
sl@0	828	case SRT_Mem: {
sl@0	829	assert( nColumn==1 );
sl@0	830	sqlite3ExprCodeMove(pParse, regRow, iParm, 1);
sl@0	831	/* The LIMIT clause will terminate the loop for us */
sl@0	832	break;
sl@0	833	}
sl@0	834	#endif
sl@0	835	case SRT_Output:
sl@0	836	case SRT_Coroutine: {
sl@0	837	int i;
sl@0	838	sqlite3VdbeAddOp2(v, OP_Integer, 1, regRowid);
sl@0	839	sqlite3VdbeAddOp3(v, OP_Insert, pseudoTab, regRow, regRowid);
sl@0	840	for(i=0; i<nColumn; i++){
sl@0	841	assert( regRow!=pDest->iMem+i );
sl@0	842	sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
sl@0	843	}
sl@0	844	if( eDest==SRT_Output ){
sl@0	845	sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
sl@0	846	sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
sl@0	847	}else{
sl@0	848	sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
sl@0	849	}
sl@0	850	break;
sl@0	851	}
sl@0	852	default: {
sl@0	853	/* Do nothing */
sl@0	854	break;
sl@0	855	}
sl@0	856	}
sl@0	857	sqlite3ReleaseTempReg(pParse, regRow);
sl@0	858	sqlite3ReleaseTempReg(pParse, regRowid);
sl@0	859
sl@0	860	/* LIMIT has been implemented by the pushOntoSorter() routine.
sl@0	861	*/
sl@0	862	assert( p->iLimit==0 );
sl@0	863
sl@0	864	/* The bottom of the loop
sl@0	865	*/
sl@0	866	sqlite3VdbeResolveLabel(v, cont);
sl@0	867	sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
sl@0	868	sqlite3VdbeResolveLabel(v, brk);
sl@0	869	if( eDest==SRT_Output \|\| eDest==SRT_Coroutine ){
sl@0	870	sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
sl@0	871	}
sl@0	872
sl@0	873	}
sl@0	874
sl@0	875	/*
sl@0	876	** Return a pointer to a string containing the 'declaration type' of the
sl@0	877	** expression pExpr. The string may be treated as static by the caller.
sl@0	878	**
sl@0	879	** The declaration type is the exact datatype definition extracted from the
sl@0	880	** original CREATE TABLE statement if the expression is a column. The
sl@0	881	** declaration type for a ROWID field is INTEGER. Exactly when an expression
sl@0	882	** is considered a column can be complex in the presence of subqueries. The
sl@0	883	** result-set expression in all of the following SELECT statements is
sl@0	884	** considered a column by this function.
sl@0	885	**
sl@0	886	** SELECT col FROM tbl;
sl@0	887	** SELECT (SELECT col FROM tbl;
sl@0	888	** SELECT (SELECT col FROM tbl);
sl@0	889	** SELECT abc FROM (SELECT col AS abc FROM tbl);
sl@0	890	**
sl@0	891	** The declaration type for any expression other than a column is NULL.
sl@0	892	*/
sl@0	893	static const char *columnType(
sl@0	894	NameContext *pNC,
sl@0	895	Expr *pExpr,
sl@0	896	const char **pzOriginDb,
sl@0	897	const char **pzOriginTab,
sl@0	898	const char **pzOriginCol
sl@0	899	){
sl@0	900	char const *zType = 0;
sl@0	901	char const *zOriginDb = 0;
sl@0	902	char const *zOriginTab = 0;
sl@0	903	char const *zOriginCol = 0;
sl@0	904	int j;
sl@0	905	if( pExpr==0 \|\| pNC->pSrcList==0 ) return 0;
sl@0	906
sl@0	907	switch( pExpr->op ){
sl@0	908	case TK_AGG_COLUMN:
sl@0	909	case TK_COLUMN: {
sl@0	910	/* The expression is a column. Locate the table the column is being
sl@0	911	** extracted from in NameContext.pSrcList. This table may be real
sl@0	912	** database table or a subquery.
sl@0	913	*/
sl@0	914	Table pTab = 0; / Table structure column is extracted from */
sl@0	915	Select pS = 0; / Select the column is extracted from */
sl@0	916	int iCol = pExpr->iColumn; /* Index of column in pTab */
sl@0	917	while( pNC && !pTab ){
sl@0	918	SrcList *pTabList = pNC->pSrcList;
sl@0	919	for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
sl@0	920	if( j<pTabList->nSrc ){
sl@0	921	pTab = pTabList->a[j].pTab;
sl@0	922	pS = pTabList->a[j].pSelect;
sl@0	923	}else{
sl@0	924	pNC = pNC->pNext;
sl@0	925	}
sl@0	926	}
sl@0	927
sl@0	928	if( pTab==0 ){
sl@0	929	/* FIX ME:
sl@0	930	** This can occurs if you have something like "SELECT new.x;" inside
sl@0	931	** a trigger. In other words, if you reference the special "new"
sl@0	932	** table in the result set of a select. We do not have a good way
sl@0	933	** to find the actual table type, so call it "TEXT". This is really
sl@0	934	** something of a bug, but I do not know how to fix it.
sl@0	935	**
sl@0	936	** This code does not produce the correct answer - it just prevents
sl@0	937	** a segfault. See ticket #1229.
sl@0	938	*/
sl@0	939	zType = "TEXT";
sl@0	940	break;
sl@0	941	}
sl@0	942
sl@0	943	assert( pTab );
sl@0	944	if( pS ){
sl@0	945	/* The "table" is actually a sub-select or a view in the FROM clause
sl@0	946	** of the SELECT statement. Return the declaration type and origin
sl@0	947	** data for the result-set column of the sub-select.
sl@0	948	*/
sl@0	949	if( iCol>=0 && iCol<pS->pEList->nExpr ){
sl@0	950	/* If iCol is less than zero, then the expression requests the
sl@0	951	** rowid of the sub-select or view. This expression is legal (see
sl@0	952	** test case misc2.2.2) - it always evaluates to NULL.
sl@0	953	*/
sl@0	954	NameContext sNC;
sl@0	955	Expr *p = pS->pEList->a[iCol].pExpr;
sl@0	956	sNC.pSrcList = pS->pSrc;
sl@0	957	sNC.pNext = 0;
sl@0	958	sNC.pParse = pNC->pParse;
sl@0	959	zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
sl@0	960	}
sl@0	961	}else if( pTab->pSchema ){
sl@0	962	/* A real table */
sl@0	963	assert( !pS );
sl@0	964	if( iCol<0 ) iCol = pTab->iPKey;
sl@0	965	assert( iCol==-1 \|\| (iCol>=0 && iCol<pTab->nCol) );
sl@0	966	if( iCol<0 ){
sl@0	967	zType = "INTEGER";
sl@0	968	zOriginCol = "rowid";
sl@0	969	}else{
sl@0	970	zType = pTab->aCol[iCol].zType;
sl@0	971	zOriginCol = pTab->aCol[iCol].zName;
sl@0	972	}
sl@0	973	zOriginTab = pTab->zName;
sl@0	974	if( pNC->pParse ){
sl@0	975	int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
sl@0	976	zOriginDb = pNC->pParse->db->aDb[iDb].zName;
sl@0	977	}
sl@0	978	}
sl@0	979	break;
sl@0	980	}
sl@0	981	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	982	case TK_SELECT: {
sl@0	983	/* The expression is a sub-select. Return the declaration type and
sl@0	984	** origin info for the single column in the result set of the SELECT
sl@0	985	** statement.
sl@0	986	*/
sl@0	987	NameContext sNC;
sl@0	988	Select *pS = pExpr->pSelect;
sl@0	989	Expr *p = pS->pEList->a[0].pExpr;
sl@0	990	sNC.pSrcList = pS->pSrc;
sl@0	991	sNC.pNext = pNC;
sl@0	992	sNC.pParse = pNC->pParse;
sl@0	993	zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
sl@0	994	break;
sl@0	995	}
sl@0	996	#endif
sl@0	997	}
sl@0	998
sl@0	999	if( pzOriginDb ){
sl@0	1000	assert( pzOriginTab && pzOriginCol );
sl@0	1001	*pzOriginDb = zOriginDb;
sl@0	1002	*pzOriginTab = zOriginTab;
sl@0	1003	*pzOriginCol = zOriginCol;
sl@0	1004	}
sl@0	1005	return zType;
sl@0	1006	}
sl@0	1007
sl@0	1008	/*
sl@0	1009	** Generate code that will tell the VDBE the declaration types of columns
sl@0	1010	** in the result set.
sl@0	1011	*/
sl@0	1012	static void generateColumnTypes(
sl@0	1013	Parse pParse, / Parser context */
sl@0	1014	SrcList pTabList, / List of tables */
sl@0	1015	ExprList pEList / Expressions defining the result set */
sl@0	1016	){
sl@0	1017	#ifndef SQLITE_OMIT_DECLTYPE
sl@0	1018	Vdbe *v = pParse->pVdbe;
sl@0	1019	int i;
sl@0	1020	NameContext sNC;
sl@0	1021	sNC.pSrcList = pTabList;
sl@0	1022	sNC.pParse = pParse;
sl@0	1023	for(i=0; i<pEList->nExpr; i++){
sl@0	1024	Expr *p = pEList->a[i].pExpr;
sl@0	1025	const char *zType;
sl@0	1026	#ifdef SQLITE_ENABLE_COLUMN_METADATA
sl@0	1027	const char *zOrigDb = 0;
sl@0	1028	const char *zOrigTab = 0;
sl@0	1029	const char *zOrigCol = 0;
sl@0	1030	zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
sl@0	1031
sl@0	1032	/* The vdbe must make its own copy of the column-type and other
sl@0	1033	** column specific strings, in case the schema is reset before this
sl@0	1034	** virtual machine is deleted.
sl@0	1035	*/
sl@0	1036	sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, P4_TRANSIENT);
sl@0	1037	sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, P4_TRANSIENT);
sl@0	1038	sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, P4_TRANSIENT);
sl@0	1039	#else
sl@0	1040	zType = columnType(&sNC, p, 0, 0, 0);
sl@0	1041	#endif
sl@0	1042	sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, P4_TRANSIENT);
sl@0	1043	}
sl@0	1044	#endif /* SQLITE_OMIT_DECLTYPE */
sl@0	1045	}
sl@0	1046
sl@0	1047	/*
sl@0	1048	** Generate code that will tell the VDBE the names of columns
sl@0	1049	** in the result set. This information is used to provide the
sl@0	1050	** azCol[] values in the callback.
sl@0	1051	*/
sl@0	1052	static void generateColumnNames(
sl@0	1053	Parse pParse, / Parser context */
sl@0	1054	SrcList pTabList, / List of tables */
sl@0	1055	ExprList pEList / Expressions defining the result set */
sl@0	1056	){
sl@0	1057	Vdbe *v = pParse->pVdbe;
sl@0	1058	int i, j;
sl@0	1059	sqlite3 *db = pParse->db;
sl@0	1060	int fullNames, shortNames;
sl@0	1061
sl@0	1062	#ifndef SQLITE_OMIT_EXPLAIN
sl@0	1063	/* If this is an EXPLAIN, skip this step */
sl@0	1064	if( pParse->explain ){
sl@0	1065	return;
sl@0	1066	}
sl@0	1067	#endif
sl@0	1068
sl@0	1069	assert( v!=0 );
sl@0	1070	if( pParse->colNamesSet \|\| v==0 \|\| db->mallocFailed ) return;
sl@0	1071	pParse->colNamesSet = 1;
sl@0	1072	fullNames = (db->flags & SQLITE_FullColNames)!=0;
sl@0	1073	shortNames = (db->flags & SQLITE_ShortColNames)!=0;
sl@0	1074	sqlite3VdbeSetNumCols(v, pEList->nExpr);
sl@0	1075	for(i=0; i<pEList->nExpr; i++){
sl@0	1076	Expr *p;
sl@0	1077	p = pEList->a[i].pExpr;
sl@0	1078	if( p==0 ) continue;
sl@0	1079	if( pEList->a[i].zName ){
sl@0	1080	char *zName = pEList->a[i].zName;
sl@0	1081	sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, strlen(zName));
sl@0	1082	}else if( (p->op==TK_COLUMN \|\| p->op==TK_AGG_COLUMN) && pTabList ){
sl@0	1083	Table *pTab;
sl@0	1084	char *zCol;
sl@0	1085	int iCol = p->iColumn;
sl@0	1086	for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
sl@0	1087	assert( j<pTabList->nSrc );
sl@0	1088	pTab = pTabList->a[j].pTab;
sl@0	1089	if( iCol<0 ) iCol = pTab->iPKey;
sl@0	1090	assert( iCol==-1 \|\| (iCol>=0 && iCol<pTab->nCol) );
sl@0	1091	if( iCol<0 ){
sl@0	1092	zCol = "rowid";
sl@0	1093	}else{
sl@0	1094	zCol = pTab->aCol[iCol].zName;
sl@0	1095	}
sl@0	1096	if( !shortNames && !fullNames ){
sl@0	1097	sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
sl@0	1098	}else if( fullNames \|\| (!shortNames && pTabList->nSrc>1) ){
sl@0	1099	char *zName = 0;
sl@0	1100	char *zTab;
sl@0	1101
sl@0	1102	zTab = pTabList->a[j].zAlias;
sl@0	1103	if( fullNames \|\| zTab==0 ) zTab = pTab->zName;
sl@0	1104	zName = sqlite3MPrintf(db, "%s.%s", zTab, zCol);
sl@0	1105	sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, P4_DYNAMIC);
sl@0	1106	}else{
sl@0	1107	sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, strlen(zCol));
sl@0	1108	}
sl@0	1109	}else{
sl@0	1110	sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
sl@0	1111	}
sl@0	1112	}
sl@0	1113	generateColumnTypes(pParse, pTabList, pEList);
sl@0	1114	}
sl@0	1115
sl@0	1116	#ifndef SQLITE_OMIT_COMPOUND_SELECT
sl@0	1117	/*
sl@0	1118	** Name of the connection operator, used for error messages.
sl@0	1119	*/
sl@0	1120	static const char *selectOpName(int id){
sl@0	1121	char *z;
sl@0	1122	switch( id ){
sl@0	1123	case TK_ALL: z = "UNION ALL"; break;
sl@0	1124	case TK_INTERSECT: z = "INTERSECT"; break;
sl@0	1125	case TK_EXCEPT: z = "EXCEPT"; break;
sl@0	1126	default: z = "UNION"; break;
sl@0	1127	}
sl@0	1128	return z;
sl@0	1129	}
sl@0	1130	#endif /* SQLITE_OMIT_COMPOUND_SELECT */
sl@0	1131
sl@0	1132	/*
sl@0	1133	** Given a an expression list (which is really the list of expressions
sl@0	1134	** that form the result set of a SELECT statement) compute appropriate
sl@0	1135	** column names for a table that would hold the expression list.
sl@0	1136	**
sl@0	1137	** All column names will be unique.
sl@0	1138	**
sl@0	1139	** Only the column names are computed. Column.zType, Column.zColl,
sl@0	1140	** and other fields of Column are zeroed.
sl@0	1141	**
sl@0	1142	** Return SQLITE_OK on success. If a memory allocation error occurs,
sl@0	1143	** store NULL in paCol and 0 in pnCol and return SQLITE_NOMEM.
sl@0	1144	*/
sl@0	1145	static int selectColumnsFromExprList(
sl@0	1146	Parse pParse, / Parsing context */
sl@0	1147	ExprList pEList, / Expr list from which to derive column names */
sl@0	1148	int pnCol, / Write the number of columns here */
sl@0	1149	Column *paCol / Write the new column list here */
sl@0	1150	){
sl@0	1151	sqlite3 *db = pParse->db;
sl@0	1152	int i, j, cnt;
sl@0	1153	Column aCol, pCol;
sl@0	1154	int nCol;
sl@0	1155	Expr *p;
sl@0	1156	char *zName;
sl@0	1157	int nName;
sl@0	1158
sl@0	1159	*pnCol = nCol = pEList->nExpr;
sl@0	1160	aCol = paCol = sqlite3DbMallocZero(db, sizeof(aCol[0])nCol);
sl@0	1161	if( aCol==0 ) return SQLITE_NOMEM;
sl@0	1162	for(i=0, pCol=aCol; i<nCol; i++, pCol++){
sl@0	1163	/* Get an appropriate name for the column
sl@0	1164	*/
sl@0	1165	p = pEList->a[i].pExpr;
sl@0	1166	assert( p->pRight==0 \|\| p->pRight->token.z==0 \|\| p->pRight->token.z[0]!=0 );
sl@0	1167	if( (zName = pEList->a[i].zName)!=0 ){
sl@0	1168	/* If the column contains an "AS <name>" phrase, use <name> as the name */
sl@0	1169	zName = sqlite3DbStrDup(db, zName);
sl@0	1170	}else{
sl@0	1171	Expr *pCol = p;
sl@0	1172	Table *pTab;
sl@0	1173	while( pCol->op==TK_DOT ) pCol = pCol->pRight;
sl@0	1174	if( pCol->op==TK_COLUMN && (pTab = pCol->pTab)!=0 ){
sl@0	1175	/* For columns use the column name name */
sl@0	1176	int iCol = pCol->iColumn;
sl@0	1177	if( iCol<0 ) iCol = pTab->iPKey;
sl@0	1178	zName = sqlite3MPrintf(db, "%s",
sl@0	1179	iCol>=0 ? pTab->aCol[iCol].zName : "rowid");
sl@0	1180	}else{
sl@0	1181	/* Use the original text of the column expression as its name */
sl@0	1182	Token *pToken = (pCol->span.z?&pCol->span:&pCol->token);
sl@0	1183	zName = sqlite3MPrintf(db, "%T", pToken);
sl@0	1184	}
sl@0	1185	}
sl@0	1186	if( db->mallocFailed ){
sl@0	1187	sqlite3DbFree(db, zName);
sl@0	1188	break;
sl@0	1189	}
sl@0	1190	sqlite3Dequote(zName);
sl@0	1191
sl@0	1192	/* Make sure the column name is unique. If the name is not unique,
sl@0	1193	** append a integer to the name so that it becomes unique.
sl@0	1194	*/
sl@0	1195	nName = strlen(zName);
sl@0	1196	for(j=cnt=0; j<i; j++){
sl@0	1197	if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
sl@0	1198	char *zNewName;
sl@0	1199	zName[nName] = 0;
sl@0	1200	zNewName = sqlite3MPrintf(db, "%s:%d", zName, ++cnt);
sl@0	1201	sqlite3DbFree(db, zName);
sl@0	1202	zName = zNewName;
sl@0	1203	j = -1;
sl@0	1204	if( zName==0 ) break;
sl@0	1205	}
sl@0	1206	}
sl@0	1207	pCol->zName = zName;
sl@0	1208	}
sl@0	1209	if( db->mallocFailed ){
sl@0	1210	int j;
sl@0	1211	for(j=0; j<i; j++){
sl@0	1212	sqlite3DbFree(db, aCol[j].zName);
sl@0	1213	}
sl@0	1214	sqlite3DbFree(db, aCol);
sl@0	1215	*paCol = 0;
sl@0	1216	*pnCol = 0;
sl@0	1217	return SQLITE_NOMEM;
sl@0	1218	}
sl@0	1219	return SQLITE_OK;
sl@0	1220	}
sl@0	1221
sl@0	1222	/*
sl@0	1223	** Add type and collation information to a column list based on
sl@0	1224	** a SELECT statement.
sl@0	1225	**
sl@0	1226	** The column list presumably came from selectColumnNamesFromExprList().
sl@0	1227	** The column list has only names, not types or collations. This
sl@0	1228	** routine goes through and adds the types and collations.
sl@0	1229	**
sl@0	1230	** This routine requires that all indentifiers in the SELECT
sl@0	1231	** statement be resolved.
sl@0	1232	*/
sl@0	1233	static void selectAddColumnTypeAndCollation(
sl@0	1234	Parse pParse, / Parsing contexts */
sl@0	1235	int nCol, /* Number of columns */
sl@0	1236	Column aCol, / List of columns */
sl@0	1237	Select pSelect / SELECT used to determine types and collations */
sl@0	1238	){
sl@0	1239	sqlite3 *db = pParse->db;
sl@0	1240	NameContext sNC;
sl@0	1241	Column *pCol;
sl@0	1242	CollSeq *pColl;
sl@0	1243	int i;
sl@0	1244	Expr *p;
sl@0	1245	struct ExprList_item *a;
sl@0	1246
sl@0	1247	assert( pSelect!=0 );
sl@0	1248	assert( (pSelect->selFlags & SF_Resolved)!=0 );
sl@0	1249	assert( nCol==pSelect->pEList->nExpr \|\| db->mallocFailed );
sl@0	1250	if( db->mallocFailed ) return;
sl@0	1251	memset(&sNC, 0, sizeof(sNC));
sl@0	1252	sNC.pSrcList = pSelect->pSrc;
sl@0	1253	a = pSelect->pEList->a;
sl@0	1254	for(i=0, pCol=aCol; i<nCol; i++, pCol++){
sl@0	1255	p = a[i].pExpr;
sl@0	1256	pCol->zType = sqlite3DbStrDup(db, columnType(&sNC, p, 0, 0, 0));
sl@0	1257	pCol->affinity = sqlite3ExprAffinity(p);
sl@0	1258	pColl = sqlite3ExprCollSeq(pParse, p);
sl@0	1259	if( pColl ){
sl@0	1260	pCol->zColl = sqlite3DbStrDup(db, pColl->zName);
sl@0	1261	}
sl@0	1262	}
sl@0	1263	}
sl@0	1264
sl@0	1265	/*
sl@0	1266	** Given a SELECT statement, generate a Table structure that describes
sl@0	1267	** the result set of that SELECT.
sl@0	1268	*/
sl@0	1269	Table sqlite3ResultSetOfSelect(Parse pParse, Select *pSelect){
sl@0	1270	Table *pTab;
sl@0	1271	sqlite3 *db = pParse->db;
sl@0	1272	int savedFlags;
sl@0	1273
sl@0	1274	savedFlags = db->flags;
sl@0	1275	db->flags &= ~SQLITE_FullColNames;
sl@0	1276	db->flags \|= SQLITE_ShortColNames;
sl@0	1277	sqlite3SelectPrep(pParse, pSelect, 0);
sl@0	1278	if( pParse->nErr ) return 0;
sl@0	1279	while( pSelect->pPrior ) pSelect = pSelect->pPrior;
sl@0	1280	db->flags = savedFlags;
sl@0	1281	pTab = sqlite3DbMallocZero(db, sizeof(Table) );
sl@0	1282	if( pTab==0 ){
sl@0	1283	return 0;
sl@0	1284	}
sl@0	1285	pTab->db = db;
sl@0	1286	pTab->nRef = 1;
sl@0	1287	pTab->zName = 0;
sl@0	1288	selectColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
sl@0	1289	selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSelect);
sl@0	1290	pTab->iPKey = -1;
sl@0	1291	if( db->mallocFailed ){
sl@0	1292	sqlite3DeleteTable(pTab);
sl@0	1293	return 0;
sl@0	1294	}
sl@0	1295	return pTab;
sl@0	1296	}
sl@0	1297
sl@0	1298	/*
sl@0	1299	** Get a VDBE for the given parser context. Create a new one if necessary.
sl@0	1300	** If an error occurs, return NULL and leave a message in pParse.
sl@0	1301	*/
sl@0	1302	Vdbe sqlite3GetVdbe(Parse pParse){
sl@0	1303	Vdbe *v = pParse->pVdbe;
sl@0	1304	if( v==0 ){
sl@0	1305	v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
sl@0	1306	#ifndef SQLITE_OMIT_TRACE
sl@0	1307	if( v ){
sl@0	1308	sqlite3VdbeAddOp0(v, OP_Trace);
sl@0	1309	}
sl@0	1310	#endif
sl@0	1311	}
sl@0	1312	return v;
sl@0	1313	}
sl@0	1314
sl@0	1315
sl@0	1316	/*
sl@0	1317	** Compute the iLimit and iOffset fields of the SELECT based on the
sl@0	1318	** pLimit and pOffset expressions. pLimit and pOffset hold the expressions
sl@0	1319	** that appear in the original SQL statement after the LIMIT and OFFSET
sl@0	1320	** keywords. Or NULL if those keywords are omitted. iLimit and iOffset
sl@0	1321	** are the integer memory register numbers for counters used to compute
sl@0	1322	** the limit and offset. If there is no limit and/or offset, then
sl@0	1323	** iLimit and iOffset are negative.
sl@0	1324	**
sl@0	1325	** This routine changes the values of iLimit and iOffset only if
sl@0	1326	** a limit or offset is defined by pLimit and pOffset. iLimit and
sl@0	1327	** iOffset should have been preset to appropriate default values
sl@0	1328	** (usually but not always -1) prior to calling this routine.
sl@0	1329	** Only if pLimit!=0 or pOffset!=0 do the limit registers get
sl@0	1330	** redefined. The UNION ALL operator uses this property to force
sl@0	1331	** the reuse of the same limit and offset registers across multiple
sl@0	1332	** SELECT statements.
sl@0	1333	*/
sl@0	1334	static void computeLimitRegisters(Parse pParse, Select p, int iBreak){
sl@0	1335	Vdbe *v = 0;
sl@0	1336	int iLimit = 0;
sl@0	1337	int iOffset;
sl@0	1338	int addr1;
sl@0	1339	if( p->iLimit ) return;
sl@0	1340
sl@0	1341	/*
sl@0	1342	** "LIMIT -1" always shows all rows. There is some
sl@0	1343	** contraversy about what the correct behavior should be.
sl@0	1344	** The current implementation interprets "LIMIT 0" to mean
sl@0	1345	** no rows.
sl@0	1346	*/
sl@0	1347	if( p->pLimit ){
sl@0	1348	p->iLimit = iLimit = ++pParse->nMem;
sl@0	1349	v = sqlite3GetVdbe(pParse);
sl@0	1350	if( v==0 ) return;
sl@0	1351	sqlite3ExprCode(pParse, p->pLimit, iLimit);
sl@0	1352	sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
sl@0	1353	VdbeComment((v, "LIMIT counter"));
sl@0	1354	sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
sl@0	1355	}
sl@0	1356	if( p->pOffset ){
sl@0	1357	p->iOffset = iOffset = ++pParse->nMem;
sl@0	1358	if( p->pLimit ){
sl@0	1359	pParse->nMem++; /* Allocate an extra register for limit+offset */
sl@0	1360	}
sl@0	1361	v = sqlite3GetVdbe(pParse);
sl@0	1362	if( v==0 ) return;
sl@0	1363	sqlite3ExprCode(pParse, p->pOffset, iOffset);
sl@0	1364	sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
sl@0	1365	VdbeComment((v, "OFFSET counter"));
sl@0	1366	addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset);
sl@0	1367	sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
sl@0	1368	sqlite3VdbeJumpHere(v, addr1);
sl@0	1369	if( p->pLimit ){
sl@0	1370	sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
sl@0	1371	VdbeComment((v, "LIMIT+OFFSET"));
sl@0	1372	addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
sl@0	1373	sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
sl@0	1374	sqlite3VdbeJumpHere(v, addr1);
sl@0	1375	}
sl@0	1376	}
sl@0	1377	}
sl@0	1378
sl@0	1379	#ifndef SQLITE_OMIT_COMPOUND_SELECT
sl@0	1380	/*
sl@0	1381	** Return the appropriate collating sequence for the iCol-th column of
sl@0	1382	** the result set for the compound-select statement "p". Return NULL if
sl@0	1383	** the column has no default collating sequence.
sl@0	1384	**
sl@0	1385	** The collating sequence for the compound select is taken from the
sl@0	1386	** left-most term of the select that has a collating sequence.
sl@0	1387	*/
sl@0	1388	static CollSeq multiSelectCollSeq(Parse pParse, Select *p, int iCol){
sl@0	1389	CollSeq *pRet;
sl@0	1390	if( p->pPrior ){
sl@0	1391	pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
sl@0	1392	}else{
sl@0	1393	pRet = 0;
sl@0	1394	}
sl@0	1395	if( pRet==0 ){
sl@0	1396	pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
sl@0	1397	}
sl@0	1398	return pRet;
sl@0	1399	}
sl@0	1400	#endif /* SQLITE_OMIT_COMPOUND_SELECT */
sl@0	1401
sl@0	1402	/* Forward reference */
sl@0	1403	static int multiSelectOrderBy(
sl@0	1404	Parse pParse, / Parsing context */
sl@0	1405	Select p, / The right-most of SELECTs to be coded */
sl@0	1406	SelectDest pDest / What to do with query results */
sl@0	1407	);
sl@0	1408
sl@0	1409
sl@0	1410	#ifndef SQLITE_OMIT_COMPOUND_SELECT
sl@0	1411	/*
sl@0	1412	** This routine is called to process a compound query form from
sl@0	1413	** two or more separate queries using UNION, UNION ALL, EXCEPT, or
sl@0	1414	** INTERSECT
sl@0	1415	**
sl@0	1416	** "p" points to the right-most of the two queries. the query on the
sl@0	1417	** left is p->pPrior. The left query could also be a compound query
sl@0	1418	** in which case this routine will be called recursively.
sl@0	1419	**
sl@0	1420	** The results of the total query are to be written into a destination
sl@0	1421	** of type eDest with parameter iParm.
sl@0	1422	**
sl@0	1423	** Example 1: Consider a three-way compound SQL statement.
sl@0	1424	**
sl@0	1425	** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
sl@0	1426	**
sl@0	1427	** This statement is parsed up as follows:
sl@0	1428	**
sl@0	1429	** SELECT c FROM t3
sl@0	1430	** \|
sl@0	1431	** `-----> SELECT b FROM t2
sl@0	1432	** \|
sl@0	1433	** `------> SELECT a FROM t1
sl@0	1434	**
sl@0	1435	** The arrows in the diagram above represent the Select.pPrior pointer.
sl@0	1436	** So if this routine is called with p equal to the t3 query, then
sl@0	1437	** pPrior will be the t2 query. p->op will be TK_UNION in this case.
sl@0	1438	**
sl@0	1439	** Notice that because of the way SQLite parses compound SELECTs, the
sl@0	1440	** individual selects always group from left to right.
sl@0	1441	*/
sl@0	1442	static int multiSelect(
sl@0	1443	Parse pParse, / Parsing context */
sl@0	1444	Select p, / The right-most of SELECTs to be coded */
sl@0	1445	SelectDest pDest / What to do with query results */
sl@0	1446	){
sl@0	1447	int rc = SQLITE_OK; /* Success code from a subroutine */
sl@0	1448	Select pPrior; / Another SELECT immediately to our left */
sl@0	1449	Vdbe v; / Generate code to this VDBE */
sl@0	1450	SelectDest dest; /* Alternative data destination */
sl@0	1451	Select pDelete = 0; / Chain of simple selects to delete */
sl@0	1452	sqlite3 db; / Database connection */
sl@0	1453
sl@0	1454	/* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
sl@0	1455	** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
sl@0	1456	*/
sl@0	1457	assert( p && p->pPrior ); /* Calling function guarantees this much */
sl@0	1458	db = pParse->db;
sl@0	1459	pPrior = p->pPrior;
sl@0	1460	assert( pPrior->pRightmost!=pPrior );
sl@0	1461	assert( pPrior->pRightmost==p->pRightmost );
sl@0	1462	dest = *pDest;
sl@0	1463	if( pPrior->pOrderBy ){
sl@0	1464	sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
sl@0	1465	selectOpName(p->op));
sl@0	1466	rc = 1;
sl@0	1467	goto multi_select_end;
sl@0	1468	}
sl@0	1469	if( pPrior->pLimit ){
sl@0	1470	sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
sl@0	1471	selectOpName(p->op));
sl@0	1472	rc = 1;
sl@0	1473	goto multi_select_end;
sl@0	1474	}
sl@0	1475
sl@0	1476	v = sqlite3GetVdbe(pParse);
sl@0	1477	assert( v!=0 ); /* The VDBE already created by calling function */
sl@0	1478
sl@0	1479	/* Create the destination temporary table if necessary
sl@0	1480	*/
sl@0	1481	if( dest.eDest==SRT_EphemTab ){
sl@0	1482	assert( p->pEList );
sl@0	1483	sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, p->pEList->nExpr);
sl@0	1484	dest.eDest = SRT_Table;
sl@0	1485	}
sl@0	1486
sl@0	1487	/* Make sure all SELECTs in the statement have the same number of elements
sl@0	1488	** in their result sets.
sl@0	1489	*/
sl@0	1490	assert( p->pEList && pPrior->pEList );
sl@0	1491	if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
sl@0	1492	sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
sl@0	1493	" do not have the same number of result columns", selectOpName(p->op));
sl@0	1494	rc = 1;
sl@0	1495	goto multi_select_end;
sl@0	1496	}
sl@0	1497
sl@0	1498	/* Compound SELECTs that have an ORDER BY clause are handled separately.
sl@0	1499	*/
sl@0	1500	if( p->pOrderBy ){
sl@0	1501	return multiSelectOrderBy(pParse, p, pDest);
sl@0	1502	}
sl@0	1503
sl@0	1504	/* Generate code for the left and right SELECT statements.
sl@0	1505	*/
sl@0	1506	switch( p->op ){
sl@0	1507	case TK_ALL: {
sl@0	1508	int addr = 0;
sl@0	1509	assert( !pPrior->pLimit );
sl@0	1510	pPrior->pLimit = p->pLimit;
sl@0	1511	pPrior->pOffset = p->pOffset;
sl@0	1512	rc = sqlite3Select(pParse, pPrior, &dest);
sl@0	1513	p->pLimit = 0;
sl@0	1514	p->pOffset = 0;
sl@0	1515	if( rc ){
sl@0	1516	goto multi_select_end;
sl@0	1517	}
sl@0	1518	p->pPrior = 0;
sl@0	1519	p->iLimit = pPrior->iLimit;
sl@0	1520	p->iOffset = pPrior->iOffset;
sl@0	1521	if( p->iLimit ){
sl@0	1522	addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
sl@0	1523	VdbeComment((v, "Jump ahead if LIMIT reached"));
sl@0	1524	}
sl@0	1525	rc = sqlite3Select(pParse, p, &dest);
sl@0	1526	pDelete = p->pPrior;
sl@0	1527	p->pPrior = pPrior;
sl@0	1528	if( rc ){
sl@0	1529	goto multi_select_end;
sl@0	1530	}
sl@0	1531	if( addr ){
sl@0	1532	sqlite3VdbeJumpHere(v, addr);
sl@0	1533	}
sl@0	1534	break;
sl@0	1535	}
sl@0	1536	case TK_EXCEPT:
sl@0	1537	case TK_UNION: {
sl@0	1538	int unionTab; /* Cursor number of the temporary table holding result */
sl@0	1539	int op = 0; /* One of the SRT_ operations to apply to self */
sl@0	1540	int priorOp; /* The SRT_ operation to apply to prior selects */
sl@0	1541	Expr pLimit, pOffset; /* Saved values of p->nLimit and p->nOffset */
sl@0	1542	int addr;
sl@0	1543	SelectDest uniondest;
sl@0	1544
sl@0	1545	priorOp = SRT_Union;
sl@0	1546	if( dest.eDest==priorOp && !p->pLimit && !p->pOffset ){
sl@0	1547	/* We can reuse a temporary table generated by a SELECT to our
sl@0	1548	** right.
sl@0	1549	*/
sl@0	1550	unionTab = dest.iParm;
sl@0	1551	}else{
sl@0	1552	/* We will need to create our own temporary table to hold the
sl@0	1553	** intermediate results.
sl@0	1554	*/
sl@0	1555	unionTab = pParse->nTab++;
sl@0	1556	assert( p->pOrderBy==0 );
sl@0	1557	addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
sl@0	1558	assert( p->addrOpenEphm[0] == -1 );
sl@0	1559	p->addrOpenEphm[0] = addr;
sl@0	1560	p->pRightmost->selFlags \|= SF_UsesEphemeral;
sl@0	1561	assert( p->pEList );
sl@0	1562	}
sl@0	1563
sl@0	1564	/* Code the SELECT statements to our left
sl@0	1565	*/
sl@0	1566	assert( !pPrior->pOrderBy );
sl@0	1567	sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
sl@0	1568	rc = sqlite3Select(pParse, pPrior, &uniondest);
sl@0	1569	if( rc ){
sl@0	1570	goto multi_select_end;
sl@0	1571	}
sl@0	1572
sl@0	1573	/* Code the current SELECT statement
sl@0	1574	*/
sl@0	1575	if( p->op==TK_EXCEPT ){
sl@0	1576	op = SRT_Except;
sl@0	1577	}else{
sl@0	1578	assert( p->op==TK_UNION );
sl@0	1579	op = SRT_Union;
sl@0	1580	}
sl@0	1581	p->pPrior = 0;
sl@0	1582	pLimit = p->pLimit;
sl@0	1583	p->pLimit = 0;
sl@0	1584	pOffset = p->pOffset;
sl@0	1585	p->pOffset = 0;
sl@0	1586	uniondest.eDest = op;
sl@0	1587	rc = sqlite3Select(pParse, p, &uniondest);
sl@0	1588	/* Query flattening in sqlite3Select() might refill p->pOrderBy.
sl@0	1589	** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
sl@0	1590	sqlite3ExprListDelete(db, p->pOrderBy);
sl@0	1591	pDelete = p->pPrior;
sl@0	1592	p->pPrior = pPrior;
sl@0	1593	p->pOrderBy = 0;
sl@0	1594	sqlite3ExprDelete(db, p->pLimit);
sl@0	1595	p->pLimit = pLimit;
sl@0	1596	p->pOffset = pOffset;
sl@0	1597	p->iLimit = 0;
sl@0	1598	p->iOffset = 0;
sl@0	1599	if( rc ){
sl@0	1600	goto multi_select_end;
sl@0	1601	}
sl@0	1602
sl@0	1603
sl@0	1604	/* Convert the data in the temporary table into whatever form
sl@0	1605	** it is that we currently need.
sl@0	1606	*/
sl@0	1607	if( dest.eDest!=priorOp \|\| unionTab!=dest.iParm ){
sl@0	1608	int iCont, iBreak, iStart;
sl@0	1609	assert( p->pEList );
sl@0	1610	if( dest.eDest==SRT_Output ){
sl@0	1611	Select *pFirst = p;
sl@0	1612	while( pFirst->pPrior ) pFirst = pFirst->pPrior;
sl@0	1613	generateColumnNames(pParse, 0, pFirst->pEList);
sl@0	1614	}
sl@0	1615	iBreak = sqlite3VdbeMakeLabel(v);
sl@0	1616	iCont = sqlite3VdbeMakeLabel(v);
sl@0	1617	computeLimitRegisters(pParse, p, iBreak);
sl@0	1618	sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak);
sl@0	1619	iStart = sqlite3VdbeCurrentAddr(v);
sl@0	1620	selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
sl@0	1621	0, -1, &dest, iCont, iBreak);
sl@0	1622	sqlite3VdbeResolveLabel(v, iCont);
sl@0	1623	sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart);
sl@0	1624	sqlite3VdbeResolveLabel(v, iBreak);
sl@0	1625	sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
sl@0	1626	}
sl@0	1627	break;
sl@0	1628	}
sl@0	1629	case TK_INTERSECT: {
sl@0	1630	int tab1, tab2;
sl@0	1631	int iCont, iBreak, iStart;
sl@0	1632	Expr pLimit, pOffset;
sl@0	1633	int addr;
sl@0	1634	SelectDest intersectdest;
sl@0	1635	int r1;
sl@0	1636
sl@0	1637	/* INTERSECT is different from the others since it requires
sl@0	1638	** two temporary tables. Hence it has its own case. Begin
sl@0	1639	** by allocating the tables we will need.
sl@0	1640	*/
sl@0	1641	tab1 = pParse->nTab++;
sl@0	1642	tab2 = pParse->nTab++;
sl@0	1643	assert( p->pOrderBy==0 );
sl@0	1644
sl@0	1645	addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
sl@0	1646	assert( p->addrOpenEphm[0] == -1 );
sl@0	1647	p->addrOpenEphm[0] = addr;
sl@0	1648	p->pRightmost->selFlags \|= SF_UsesEphemeral;
sl@0	1649	assert( p->pEList );
sl@0	1650
sl@0	1651	/* Code the SELECTs to our left into temporary table "tab1".
sl@0	1652	*/
sl@0	1653	sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
sl@0	1654	rc = sqlite3Select(pParse, pPrior, &intersectdest);
sl@0	1655	if( rc ){
sl@0	1656	goto multi_select_end;
sl@0	1657	}
sl@0	1658
sl@0	1659	/* Code the current SELECT into temporary table "tab2"
sl@0	1660	*/
sl@0	1661	addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
sl@0	1662	assert( p->addrOpenEphm[1] == -1 );
sl@0	1663	p->addrOpenEphm[1] = addr;
sl@0	1664	p->pPrior = 0;
sl@0	1665	pLimit = p->pLimit;
sl@0	1666	p->pLimit = 0;
sl@0	1667	pOffset = p->pOffset;
sl@0	1668	p->pOffset = 0;
sl@0	1669	intersectdest.iParm = tab2;
sl@0	1670	rc = sqlite3Select(pParse, p, &intersectdest);
sl@0	1671	pDelete = p->pPrior;
sl@0	1672	p->pPrior = pPrior;
sl@0	1673	sqlite3ExprDelete(db, p->pLimit);
sl@0	1674	p->pLimit = pLimit;
sl@0	1675	p->pOffset = pOffset;
sl@0	1676	if( rc ){
sl@0	1677	goto multi_select_end;
sl@0	1678	}
sl@0	1679
sl@0	1680	/* Generate code to take the intersection of the two temporary
sl@0	1681	** tables.
sl@0	1682	*/
sl@0	1683	assert( p->pEList );
sl@0	1684	if( dest.eDest==SRT_Output ){
sl@0	1685	Select *pFirst = p;
sl@0	1686	while( pFirst->pPrior ) pFirst = pFirst->pPrior;
sl@0	1687	generateColumnNames(pParse, 0, pFirst->pEList);
sl@0	1688	}
sl@0	1689	iBreak = sqlite3VdbeMakeLabel(v);
sl@0	1690	iCont = sqlite3VdbeMakeLabel(v);
sl@0	1691	computeLimitRegisters(pParse, p, iBreak);
sl@0	1692	sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
sl@0	1693	r1 = sqlite3GetTempReg(pParse);
sl@0	1694	iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
sl@0	1695	sqlite3VdbeAddOp3(v, OP_NotFound, tab2, iCont, r1);
sl@0	1696	sqlite3ReleaseTempReg(pParse, r1);
sl@0	1697	selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
sl@0	1698	0, -1, &dest, iCont, iBreak);
sl@0	1699	sqlite3VdbeResolveLabel(v, iCont);
sl@0	1700	sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
sl@0	1701	sqlite3VdbeResolveLabel(v, iBreak);
sl@0	1702	sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
sl@0	1703	sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
sl@0	1704	break;
sl@0	1705	}
sl@0	1706	}
sl@0	1707
sl@0	1708	/* Compute collating sequences used by
sl@0	1709	** temporary tables needed to implement the compound select.
sl@0	1710	** Attach the KeyInfo structure to all temporary tables.
sl@0	1711	**
sl@0	1712	** This section is run by the right-most SELECT statement only.
sl@0	1713	** SELECT statements to the left always skip this part. The right-most
sl@0	1714	** SELECT might also skip this part if it has no ORDER BY clause and
sl@0	1715	** no temp tables are required.
sl@0	1716	*/
sl@0	1717	if( p->selFlags & SF_UsesEphemeral ){
sl@0	1718	int i; /* Loop counter */
sl@0	1719	KeyInfo pKeyInfo; / Collating sequence for the result set */
sl@0	1720	Select pLoop; / For looping through SELECT statements */
sl@0	1721	CollSeq *apColl; / For looping through pKeyInfo->aColl[] */
sl@0	1722	int nCol; /* Number of columns in result set */
sl@0	1723
sl@0	1724	assert( p->pRightmost==p );
sl@0	1725	nCol = p->pEList->nExpr;
sl@0	1726	pKeyInfo = sqlite3DbMallocZero(db,
sl@0	1727	sizeof(pKeyInfo)+nCol(sizeof(CollSeq*) + 1));
sl@0	1728	if( !pKeyInfo ){
sl@0	1729	rc = SQLITE_NOMEM;
sl@0	1730	goto multi_select_end;
sl@0	1731	}
sl@0	1732
sl@0	1733	pKeyInfo->enc = ENC(db);
sl@0	1734	pKeyInfo->nField = nCol;
sl@0	1735
sl@0	1736	for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
sl@0	1737	*apColl = multiSelectCollSeq(pParse, p, i);
sl@0	1738	if( 0==*apColl ){
sl@0	1739	*apColl = db->pDfltColl;
sl@0	1740	}
sl@0	1741	}
sl@0	1742
sl@0	1743	for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
sl@0	1744	for(i=0; i<2; i++){
sl@0	1745	int addr = pLoop->addrOpenEphm[i];
sl@0	1746	if( addr<0 ){
sl@0	1747	/* If [0] is unused then [1] is also unused. So we can
sl@0	1748	** always safely abort as soon as the first unused slot is found */
sl@0	1749	assert( pLoop->addrOpenEphm[1]<0 );
sl@0	1750	break;
sl@0	1751	}
sl@0	1752	sqlite3VdbeChangeP2(v, addr, nCol);
sl@0	1753	sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
sl@0	1754	pLoop->addrOpenEphm[i] = -1;
sl@0	1755	}
sl@0	1756	}
sl@0	1757	sqlite3DbFree(db, pKeyInfo);
sl@0	1758	}
sl@0	1759
sl@0	1760	multi_select_end:
sl@0	1761	pDest->iMem = dest.iMem;
sl@0	1762	pDest->nMem = dest.nMem;
sl@0	1763	sqlite3SelectDelete(db, pDelete);
sl@0	1764	return rc;
sl@0	1765	}
sl@0	1766	#endif /* SQLITE_OMIT_COMPOUND_SELECT */
sl@0	1767
sl@0	1768	/*
sl@0	1769	** Code an output subroutine for a coroutine implementation of a
sl@0	1770	** SELECT statment.
sl@0	1771	**
sl@0	1772	** The data to be output is contained in pIn->iMem. There are
sl@0	1773	** pIn->nMem columns to be output. pDest is where the output should
sl@0	1774	** be sent.
sl@0	1775	**
sl@0	1776	** regReturn is the number of the register holding the subroutine
sl@0	1777	** return address.
sl@0	1778	**
sl@0	1779	** If regPrev>0 then it is a the first register in a vector that
sl@0	1780	** records the previous output. mem[regPrev] is a flag that is false
sl@0	1781	** if there has been no previous output. If regPrev>0 then code is
sl@0	1782	** generated to suppress duplicates. pKeyInfo is used for comparing
sl@0	1783	** keys.
sl@0	1784	**
sl@0	1785	** If the LIMIT found in p->iLimit is reached, jump immediately to
sl@0	1786	** iBreak.
sl@0	1787	*/
sl@0	1788	static int generateOutputSubroutine(
sl@0	1789	Parse pParse, / Parsing context */
sl@0	1790	Select p, / The SELECT statement */
sl@0	1791	SelectDest pIn, / Coroutine supplying data */
sl@0	1792	SelectDest pDest, / Where to send the data */
sl@0	1793	int regReturn, /* The return address register */
sl@0	1794	int regPrev, /* Previous result register. No uniqueness if 0 */
sl@0	1795	KeyInfo pKeyInfo, / For comparing with previous entry */
sl@0	1796	int p4type, /* The p4 type for pKeyInfo */
sl@0	1797	int iBreak /* Jump here if we hit the LIMIT */
sl@0	1798	){
sl@0	1799	Vdbe *v = pParse->pVdbe;
sl@0	1800	int iContinue;
sl@0	1801	int addr;
sl@0	1802
sl@0	1803	addr = sqlite3VdbeCurrentAddr(v);
sl@0	1804	iContinue = sqlite3VdbeMakeLabel(v);
sl@0	1805
sl@0	1806	/* Suppress duplicates for UNION, EXCEPT, and INTERSECT
sl@0	1807	*/
sl@0	1808	if( regPrev ){
sl@0	1809	int j1, j2;
sl@0	1810	j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
sl@0	1811	j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iMem, regPrev+1, pIn->nMem,
sl@0	1812	(char*)pKeyInfo, p4type);
sl@0	1813	sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
sl@0	1814	sqlite3VdbeJumpHere(v, j1);
sl@0	1815	sqlite3ExprCodeCopy(pParse, pIn->iMem, regPrev+1, pIn->nMem);
sl@0	1816	sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
sl@0	1817	}
sl@0	1818	if( pParse->db->mallocFailed ) return 0;
sl@0	1819
sl@0	1820	/* Suppress the the first OFFSET entries if there is an OFFSET clause
sl@0	1821	*/
sl@0	1822	codeOffset(v, p, iContinue);
sl@0	1823
sl@0	1824	switch( pDest->eDest ){
sl@0	1825	/* Store the result as data using a unique key.
sl@0	1826	*/
sl@0	1827	case SRT_Table:
sl@0	1828	case SRT_EphemTab: {
sl@0	1829	int r1 = sqlite3GetTempReg(pParse);
sl@0	1830	int r2 = sqlite3GetTempReg(pParse);
sl@0	1831	sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iMem, pIn->nMem, r1);
sl@0	1832	sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iParm, r2);
sl@0	1833	sqlite3VdbeAddOp3(v, OP_Insert, pDest->iParm, r1, r2);
sl@0	1834	sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
sl@0	1835	sqlite3ReleaseTempReg(pParse, r2);
sl@0	1836	sqlite3ReleaseTempReg(pParse, r1);
sl@0	1837	break;
sl@0	1838	}
sl@0	1839
sl@0	1840	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	1841	/* If we are creating a set for an "expr IN (SELECT ...)" construct,
sl@0	1842	** then there should be a single item on the stack. Write this
sl@0	1843	** item into the set table with bogus data.
sl@0	1844	*/
sl@0	1845	case SRT_Set: {
sl@0	1846	int r1;
sl@0	1847	assert( pIn->nMem==1 );
sl@0	1848	p->affinity =
sl@0	1849	sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affinity);
sl@0	1850	r1 = sqlite3GetTempReg(pParse);
sl@0	1851	sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iMem, 1, r1, &p->affinity, 1);
sl@0	1852	sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, 1);
sl@0	1853	sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iParm, r1);
sl@0	1854	sqlite3ReleaseTempReg(pParse, r1);
sl@0	1855	break;
sl@0	1856	}
sl@0	1857
sl@0	1858	#if 0 /* Never occurs on an ORDER BY query */
sl@0	1859	/* If any row exist in the result set, record that fact and abort.
sl@0	1860	*/
sl@0	1861	case SRT_Exists: {
sl@0	1862	sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iParm);
sl@0	1863	/* The LIMIT clause will terminate the loop for us */
sl@0	1864	break;
sl@0	1865	}
sl@0	1866	#endif
sl@0	1867
sl@0	1868	/* If this is a scalar select that is part of an expression, then
sl@0	1869	** store the results in the appropriate memory cell and break out
sl@0	1870	** of the scan loop.
sl@0	1871	*/
sl@0	1872	case SRT_Mem: {
sl@0	1873	assert( pIn->nMem==1 );
sl@0	1874	sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iParm, 1);
sl@0	1875	/* The LIMIT clause will jump out of the loop for us */
sl@0	1876	break;
sl@0	1877	}
sl@0	1878	#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
sl@0	1879
sl@0	1880	/* The results are stored in a sequence of registers
sl@0	1881	** starting at pDest->iMem. Then the co-routine yields.
sl@0	1882	*/
sl@0	1883	case SRT_Coroutine: {
sl@0	1884	if( pDest->iMem==0 ){
sl@0	1885	pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
sl@0	1886	pDest->nMem = pIn->nMem;
sl@0	1887	}
sl@0	1888	sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iMem, pDest->nMem);
sl@0	1889	sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
sl@0	1890	break;
sl@0	1891	}
sl@0	1892
sl@0	1893	/* Results are stored in a sequence of registers. Then the
sl@0	1894	** OP_ResultRow opcode is used to cause sqlite3_step() to return
sl@0	1895	** the next row of result.
sl@0	1896	*/
sl@0	1897	case SRT_Output: {
sl@0	1898	sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iMem, pIn->nMem);
sl@0	1899	sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, pIn->nMem);
sl@0	1900	break;
sl@0	1901	}
sl@0	1902
sl@0	1903	#if !defined(SQLITE_OMIT_TRIGGER)
sl@0	1904	/* Discard the results. This is used for SELECT statements inside
sl@0	1905	** the body of a TRIGGER. The purpose of such selects is to call
sl@0	1906	** user-defined functions that have side effects. We do not care
sl@0	1907	** about the actual results of the select.
sl@0	1908	*/
sl@0	1909	default: {
sl@0	1910	break;
sl@0	1911	}
sl@0	1912	#endif
sl@0	1913	}
sl@0	1914
sl@0	1915	/* Jump to the end of the loop if the LIMIT is reached.
sl@0	1916	*/
sl@0	1917	if( p->iLimit ){
sl@0	1918	sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
sl@0	1919	sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
sl@0	1920	}
sl@0	1921
sl@0	1922	/* Generate the subroutine return
sl@0	1923	*/
sl@0	1924	sqlite3VdbeResolveLabel(v, iContinue);
sl@0	1925	sqlite3VdbeAddOp1(v, OP_Return, regReturn);
sl@0	1926
sl@0	1927	return addr;
sl@0	1928	}
sl@0	1929
sl@0	1930	/*
sl@0	1931	** Alternative compound select code generator for cases when there
sl@0	1932	** is an ORDER BY clause.
sl@0	1933	**
sl@0	1934	** We assume a query of the following form:
sl@0	1935	**
sl@0	1936	** <selectA> <operator> <selectB> ORDER BY <orderbylist>
sl@0	1937	**
sl@0	1938	** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT. The idea
sl@0	1939	** is to code both <selectA> and <selectB> with the ORDER BY clause as
sl@0	1940	** co-routines. Then run the co-routines in parallel and merge the results
sl@0	1941	** into the output. In addition to the two coroutines (called selectA and
sl@0	1942	** selectB) there are 7 subroutines:
sl@0	1943	**
sl@0	1944	** outA: Move the output of the selectA coroutine into the output
sl@0	1945	** of the compound query.
sl@0	1946	**
sl@0	1947	** outB: Move the output of the selectB coroutine into the output
sl@0	1948	** of the compound query. (Only generated for UNION and
sl@0	1949	** UNION ALL. EXCEPT and INSERTSECT never output a row that
sl@0	1950	** appears only in B.)
sl@0	1951	**
sl@0	1952	** AltB: Called when there is data from both coroutines and A<B.
sl@0	1953	**
sl@0	1954	** AeqB: Called when there is data from both coroutines and A==B.
sl@0	1955	**
sl@0	1956	** AgtB: Called when there is data from both coroutines and A>B.
sl@0	1957	**
sl@0	1958	** EofA: Called when data is exhausted from selectA.
sl@0	1959	**
sl@0	1960	** EofB: Called when data is exhausted from selectB.
sl@0	1961	**
sl@0	1962	** The implementation of the latter five subroutines depend on which
sl@0	1963	** <operator> is used:
sl@0	1964	**
sl@0	1965	**
sl@0	1966	** UNION ALL UNION EXCEPT INTERSECT
sl@0	1967	** ------------- ----------------- -------------- -----------------
sl@0	1968	** AltB: outA, nextA outA, nextA outA, nextA nextA
sl@0	1969	**
sl@0	1970	** AeqB: outA, nextA nextA nextA outA, nextA
sl@0	1971	**
sl@0	1972	** AgtB: outB, nextB outB, nextB nextB nextB
sl@0	1973	**
sl@0	1974	** EofA: outB, nextB outB, nextB halt halt
sl@0	1975	**
sl@0	1976	** EofB: outA, nextA outA, nextA outA, nextA halt
sl@0	1977	**
sl@0	1978	** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
sl@0	1979	** causes an immediate jump to EofA and an EOF on B following nextB causes
sl@0	1980	** an immediate jump to EofB. Within EofA and EofB, and EOF on entry or
sl@0	1981	** following nextX causes a jump to the end of the select processing.
sl@0	1982	**
sl@0	1983	** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
sl@0	1984	** within the output subroutine. The regPrev register set holds the previously
sl@0	1985	** output value. A comparison is made against this value and the output
sl@0	1986	** is skipped if the next results would be the same as the previous.
sl@0	1987	**
sl@0	1988	** The implementation plan is to implement the two coroutines and seven
sl@0	1989	** subroutines first, then put the control logic at the bottom. Like this:
sl@0	1990	**
sl@0	1991	** goto Init
sl@0	1992	** coA: coroutine for left query (A)
sl@0	1993	** coB: coroutine for right query (B)
sl@0	1994	** outA: output one row of A
sl@0	1995	** outB: output one row of B (UNION and UNION ALL only)
sl@0	1996	** EofA: ...
sl@0	1997	** EofB: ...
sl@0	1998	** AltB: ...
sl@0	1999	** AeqB: ...
sl@0	2000	** AgtB: ...
sl@0	2001	** Init: initialize coroutine registers
sl@0	2002	** yield coA
sl@0	2003	** if eof(A) goto EofA
sl@0	2004	** yield coB
sl@0	2005	** if eof(B) goto EofB
sl@0	2006	** Cmpr: Compare A, B
sl@0	2007	** Jump AltB, AeqB, AgtB
sl@0	2008	** End: ...
sl@0	2009	**
sl@0	2010	** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
sl@0	2011	** actually called using Gosub and they do not Return. EofA and EofB loop
sl@0	2012	** until all data is exhausted then jump to the "end" labe. AltB, AeqB,
sl@0	2013	** and AgtB jump to either L2 or to one of EofA or EofB.
sl@0	2014	*/
sl@0	2015	#ifndef SQLITE_OMIT_COMPOUND_SELECT
sl@0	2016	static int multiSelectOrderBy(
sl@0	2017	Parse pParse, / Parsing context */
sl@0	2018	Select p, / The right-most of SELECTs to be coded */
sl@0	2019	SelectDest pDest / What to do with query results */
sl@0	2020	){
sl@0	2021	int i, j; /* Loop counters */
sl@0	2022	Select pPrior; / Another SELECT immediately to our left */
sl@0	2023	Vdbe v; / Generate code to this VDBE */
sl@0	2024	SelectDest destA; /* Destination for coroutine A */
sl@0	2025	SelectDest destB; /* Destination for coroutine B */
sl@0	2026	int regAddrA; /* Address register for select-A coroutine */
sl@0	2027	int regEofA; /* Flag to indicate when select-A is complete */
sl@0	2028	int regAddrB; /* Address register for select-B coroutine */
sl@0	2029	int regEofB; /* Flag to indicate when select-B is complete */
sl@0	2030	int addrSelectA; /* Address of the select-A coroutine */
sl@0	2031	int addrSelectB; /* Address of the select-B coroutine */
sl@0	2032	int regOutA; /* Address register for the output-A subroutine */
sl@0	2033	int regOutB; /* Address register for the output-B subroutine */
sl@0	2034	int addrOutA; /* Address of the output-A subroutine */
sl@0	2035	int addrOutB; /* Address of the output-B subroutine */
sl@0	2036	int addrEofA; /* Address of the select-A-exhausted subroutine */
sl@0	2037	int addrEofB; /* Address of the select-B-exhausted subroutine */
sl@0	2038	int addrAltB; /* Address of the A<B subroutine */
sl@0	2039	int addrAeqB; /* Address of the A==B subroutine */
sl@0	2040	int addrAgtB; /* Address of the A>B subroutine */
sl@0	2041	int regLimitA; /* Limit register for select-A */
sl@0	2042	int regLimitB; /* Limit register for select-A */
sl@0	2043	int regPrev; /* A range of registers to hold previous output */
sl@0	2044	int savedLimit; /* Saved value of p->iLimit */
sl@0	2045	int savedOffset; /* Saved value of p->iOffset */
sl@0	2046	int labelCmpr; /* Label for the start of the merge algorithm */
sl@0	2047	int labelEnd; /* Label for the end of the overall SELECT stmt */
sl@0	2048	int j1; /* Jump instructions that get retargetted */
sl@0	2049	int op; /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
sl@0	2050	KeyInfo pKeyDup = 0; / Comparison information for duplicate removal */
sl@0	2051	KeyInfo pKeyMerge; / Comparison information for merging rows */
sl@0	2052	sqlite3 db; / Database connection */
sl@0	2053	ExprList pOrderBy; / The ORDER BY clause */
sl@0	2054	int nOrderBy; /* Number of terms in the ORDER BY clause */
sl@0	2055	int aPermute; / Mapping from ORDER BY terms to result set columns */
sl@0	2056
sl@0	2057	assert( p->pOrderBy!=0 );
sl@0	2058	assert( pKeyDup==0 ); /* "Managed" code needs this. Ticket #3382. */
sl@0	2059	db = pParse->db;
sl@0	2060	v = pParse->pVdbe;
sl@0	2061	if( v==0 ) return SQLITE_NOMEM;
sl@0	2062	labelEnd = sqlite3VdbeMakeLabel(v);
sl@0	2063	labelCmpr = sqlite3VdbeMakeLabel(v);
sl@0	2064
sl@0	2065
sl@0	2066	/* Patch up the ORDER BY clause
sl@0	2067	*/
sl@0	2068	op = p->op;
sl@0	2069	pPrior = p->pPrior;
sl@0	2070	assert( pPrior->pOrderBy==0 );
sl@0	2071	pOrderBy = p->pOrderBy;
sl@0	2072	assert( pOrderBy );
sl@0	2073	nOrderBy = pOrderBy->nExpr;
sl@0	2074
sl@0	2075	/* For operators other than UNION ALL we have to make sure that
sl@0	2076	** the ORDER BY clause covers every term of the result set. Add
sl@0	2077	** terms to the ORDER BY clause as necessary.
sl@0	2078	*/
sl@0	2079	if( op!=TK_ALL ){
sl@0	2080	for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
sl@0	2081	struct ExprList_item *pItem;
sl@0	2082	for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
sl@0	2083	assert( pItem->iCol>0 );
sl@0	2084	if( pItem->iCol==i ) break;
sl@0	2085	}
sl@0	2086	if( j==nOrderBy ){
sl@0	2087	Expr *pNew = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, 0);
sl@0	2088	if( pNew==0 ) return SQLITE_NOMEM;
sl@0	2089	pNew->flags \|= EP_IntValue;
sl@0	2090	pNew->iTable = i;
sl@0	2091	pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew, 0);
sl@0	2092	pOrderBy->a[nOrderBy++].iCol = i;
sl@0	2093	}
sl@0	2094	}
sl@0	2095	}
sl@0	2096
sl@0	2097	/* Compute the comparison permutation and keyinfo that is used with
sl@0	2098	** the permutation in order to comparisons to determine if the next
sl@0	2099	** row of results comes from selectA or selectB. Also add explicit
sl@0	2100	** collations to the ORDER BY clause terms so that when the subqueries
sl@0	2101	** to the right and the left are evaluated, they use the correct
sl@0	2102	** collation.
sl@0	2103	*/
sl@0	2104	aPermute = sqlite3DbMallocRaw(db, sizeof(int)*nOrderBy);
sl@0	2105	if( aPermute ){
sl@0	2106	struct ExprList_item *pItem;
sl@0	2107	for(i=0, pItem=pOrderBy->a; i<nOrderBy; i++, pItem++){
sl@0	2108	assert( pItem->iCol>0 && pItem->iCol<=p->pEList->nExpr );
sl@0	2109	aPermute[i] = pItem->iCol - 1;
sl@0	2110	}
sl@0	2111	pKeyMerge =
sl@0	2112	sqlite3DbMallocRaw(db, sizeof(pKeyMerge)+nOrderBy(sizeof(CollSeq*)+1));
sl@0	2113	if( pKeyMerge ){
sl@0	2114	pKeyMerge->aSortOrder = (u8*)&pKeyMerge->aColl[nOrderBy];
sl@0	2115	pKeyMerge->nField = nOrderBy;
sl@0	2116	pKeyMerge->enc = ENC(db);
sl@0	2117	for(i=0; i<nOrderBy; i++){
sl@0	2118	CollSeq *pColl;
sl@0	2119	Expr *pTerm = pOrderBy->a[i].pExpr;
sl@0	2120	if( pTerm->flags & EP_ExpCollate ){
sl@0	2121	pColl = pTerm->pColl;
sl@0	2122	}else{
sl@0	2123	pColl = multiSelectCollSeq(pParse, p, aPermute[i]);
sl@0	2124	pTerm->flags \|= EP_ExpCollate;
sl@0	2125	pTerm->pColl = pColl;
sl@0	2126	}
sl@0	2127	pKeyMerge->aColl[i] = pColl;
sl@0	2128	pKeyMerge->aSortOrder[i] = pOrderBy->a[i].sortOrder;
sl@0	2129	}
sl@0	2130	}
sl@0	2131	}else{
sl@0	2132	pKeyMerge = 0;
sl@0	2133	}
sl@0	2134
sl@0	2135	/* Reattach the ORDER BY clause to the query.
sl@0	2136	*/
sl@0	2137	p->pOrderBy = pOrderBy;
sl@0	2138	pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy);
sl@0	2139
sl@0	2140	/* Allocate a range of temporary registers and the KeyInfo needed
sl@0	2141	** for the logic that removes duplicate result rows when the
sl@0	2142	** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
sl@0	2143	*/
sl@0	2144	if( op==TK_ALL ){
sl@0	2145	regPrev = 0;
sl@0	2146	}else{
sl@0	2147	int nExpr = p->pEList->nExpr;
sl@0	2148	assert( nOrderBy>=nExpr );
sl@0	2149	regPrev = sqlite3GetTempRange(pParse, nExpr+1);
sl@0	2150	sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
sl@0	2151	pKeyDup = sqlite3DbMallocZero(db,
sl@0	2152	sizeof(pKeyDup) + nExpr(sizeof(CollSeq*)+1) );
sl@0	2153	if( pKeyDup ){
sl@0	2154	pKeyDup->aSortOrder = (u8*)&pKeyDup->aColl[nExpr];
sl@0	2155	pKeyDup->nField = nExpr;
sl@0	2156	pKeyDup->enc = ENC(db);
sl@0	2157	for(i=0; i<nExpr; i++){
sl@0	2158	pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
sl@0	2159	pKeyDup->aSortOrder[i] = 0;
sl@0	2160	}
sl@0	2161	}
sl@0	2162	}
sl@0	2163
sl@0	2164	/* Separate the left and the right query from one another
sl@0	2165	*/
sl@0	2166	p->pPrior = 0;
sl@0	2167	pPrior->pRightmost = 0;
sl@0	2168	sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
sl@0	2169	if( pPrior->pPrior==0 ){
sl@0	2170	sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
sl@0	2171	}
sl@0	2172
sl@0	2173	/* Compute the limit registers */
sl@0	2174	computeLimitRegisters(pParse, p, labelEnd);
sl@0	2175	if( p->iLimit && op==TK_ALL ){
sl@0	2176	regLimitA = ++pParse->nMem;
sl@0	2177	regLimitB = ++pParse->nMem;
sl@0	2178	sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
sl@0	2179	regLimitA);
sl@0	2180	sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
sl@0	2181	}else{
sl@0	2182	regLimitA = regLimitB = 0;
sl@0	2183	}
sl@0	2184	sqlite3ExprDelete(db, p->pLimit);
sl@0	2185	p->pLimit = 0;
sl@0	2186	sqlite3ExprDelete(db, p->pOffset);
sl@0	2187	p->pOffset = 0;
sl@0	2188
sl@0	2189	regAddrA = ++pParse->nMem;
sl@0	2190	regEofA = ++pParse->nMem;
sl@0	2191	regAddrB = ++pParse->nMem;
sl@0	2192	regEofB = ++pParse->nMem;
sl@0	2193	regOutA = ++pParse->nMem;
sl@0	2194	regOutB = ++pParse->nMem;
sl@0	2195	sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
sl@0	2196	sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
sl@0	2197
sl@0	2198	/* Jump past the various subroutines and coroutines to the main
sl@0	2199	** merge loop
sl@0	2200	*/
sl@0	2201	j1 = sqlite3VdbeAddOp0(v, OP_Goto);
sl@0	2202	addrSelectA = sqlite3VdbeCurrentAddr(v);
sl@0	2203
sl@0	2204
sl@0	2205	/* Generate a coroutine to evaluate the SELECT statement to the
sl@0	2206	** left of the compound operator - the "A" select.
sl@0	2207	*/
sl@0	2208	VdbeNoopComment((v, "Begin coroutine for left SELECT"));
sl@0	2209	pPrior->iLimit = regLimitA;
sl@0	2210	sqlite3Select(pParse, pPrior, &destA);
sl@0	2211	sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
sl@0	2212	sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sl@0	2213	VdbeNoopComment((v, "End coroutine for left SELECT"));
sl@0	2214
sl@0	2215	/* Generate a coroutine to evaluate the SELECT statement on
sl@0	2216	** the right - the "B" select
sl@0	2217	*/
sl@0	2218	addrSelectB = sqlite3VdbeCurrentAddr(v);
sl@0	2219	VdbeNoopComment((v, "Begin coroutine for right SELECT"));
sl@0	2220	savedLimit = p->iLimit;
sl@0	2221	savedOffset = p->iOffset;
sl@0	2222	p->iLimit = regLimitB;
sl@0	2223	p->iOffset = 0;
sl@0	2224	sqlite3Select(pParse, p, &destB);
sl@0	2225	p->iLimit = savedLimit;
sl@0	2226	p->iOffset = savedOffset;
sl@0	2227	sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
sl@0	2228	sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
sl@0	2229	VdbeNoopComment((v, "End coroutine for right SELECT"));
sl@0	2230
sl@0	2231	/* Generate a subroutine that outputs the current row of the A
sl@0	2232	** select as the next output row of the compound select.
sl@0	2233	*/
sl@0	2234	VdbeNoopComment((v, "Output routine for A"));
sl@0	2235	addrOutA = generateOutputSubroutine(pParse,
sl@0	2236	p, &destA, pDest, regOutA,
sl@0	2237	regPrev, pKeyDup, P4_KEYINFO_HANDOFF, labelEnd);
sl@0	2238
sl@0	2239	/* Generate a subroutine that outputs the current row of the B
sl@0	2240	** select as the next output row of the compound select.
sl@0	2241	*/
sl@0	2242	if( op==TK_ALL \|\| op==TK_UNION ){
sl@0	2243	VdbeNoopComment((v, "Output routine for B"));
sl@0	2244	addrOutB = generateOutputSubroutine(pParse,
sl@0	2245	p, &destB, pDest, regOutB,
sl@0	2246	regPrev, pKeyDup, P4_KEYINFO_STATIC, labelEnd);
sl@0	2247	}
sl@0	2248
sl@0	2249	/* Generate a subroutine to run when the results from select A
sl@0	2250	** are exhausted and only data in select B remains.
sl@0	2251	*/
sl@0	2252	VdbeNoopComment((v, "eof-A subroutine"));
sl@0	2253	if( op==TK_EXCEPT \|\| op==TK_INTERSECT ){
sl@0	2254	addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
sl@0	2255	}else{
sl@0	2256	addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
sl@0	2257	sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
sl@0	2258	sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
sl@0	2259	sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
sl@0	2260	}
sl@0	2261
sl@0	2262	/* Generate a subroutine to run when the results from select B
sl@0	2263	** are exhausted and only data in select A remains.
sl@0	2264	*/
sl@0	2265	if( op==TK_INTERSECT ){
sl@0	2266	addrEofB = addrEofA;
sl@0	2267	}else{
sl@0	2268	VdbeNoopComment((v, "eof-B subroutine"));
sl@0	2269	addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
sl@0	2270	sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sl@0	2271	sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sl@0	2272	sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
sl@0	2273	}
sl@0	2274
sl@0	2275	/* Generate code to handle the case of A<B
sl@0	2276	*/
sl@0	2277	VdbeNoopComment((v, "A-lt-B subroutine"));
sl@0	2278	addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sl@0	2279	sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sl@0	2280	sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
sl@0	2281	sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
sl@0	2282
sl@0	2283	/* Generate code to handle the case of A==B
sl@0	2284	*/
sl@0	2285	if( op==TK_ALL ){
sl@0	2286	addrAeqB = addrAltB;
sl@0	2287	}else if( op==TK_INTERSECT ){
sl@0	2288	addrAeqB = addrAltB;
sl@0	2289	addrAltB++;
sl@0	2290	}else{
sl@0	2291	VdbeNoopComment((v, "A-eq-B subroutine"));
sl@0	2292	addrAeqB =
sl@0	2293	sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sl@0	2294	sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
sl@0	2295	sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
sl@0	2296	}
sl@0	2297
sl@0	2298	/* Generate code to handle the case of A>B
sl@0	2299	*/
sl@0	2300	VdbeNoopComment((v, "A-gt-B subroutine"));
sl@0	2301	addrAgtB = sqlite3VdbeCurrentAddr(v);
sl@0	2302	if( op==TK_ALL \|\| op==TK_UNION ){
sl@0	2303	sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
sl@0	2304	}
sl@0	2305	sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
sl@0	2306	sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
sl@0	2307	sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
sl@0	2308
sl@0	2309	/* This code runs once to initialize everything.
sl@0	2310	*/
sl@0	2311	sqlite3VdbeJumpHere(v, j1);
sl@0	2312	sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
sl@0	2313	sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
sl@0	2314	sqlite3VdbeAddOp2(v, OP_Gosub, regAddrA, addrSelectA);
sl@0	2315	sqlite3VdbeAddOp2(v, OP_Gosub, regAddrB, addrSelectB);
sl@0	2316	sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
sl@0	2317	sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
sl@0	2318
sl@0	2319	/* Implement the main merge loop
sl@0	2320	*/
sl@0	2321	sqlite3VdbeResolveLabel(v, labelCmpr);
sl@0	2322	sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
sl@0	2323	sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, nOrderBy,
sl@0	2324	(char*)pKeyMerge, P4_KEYINFO_HANDOFF);
sl@0	2325	sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);
sl@0	2326
sl@0	2327	/* Release temporary registers
sl@0	2328	*/
sl@0	2329	if( regPrev ){
sl@0	2330	sqlite3ReleaseTempRange(pParse, regPrev, nOrderBy+1);
sl@0	2331	}
sl@0	2332
sl@0	2333	/* Jump to the this point in order to terminate the query.
sl@0	2334	*/
sl@0	2335	sqlite3VdbeResolveLabel(v, labelEnd);
sl@0	2336
sl@0	2337	/* Set the number of output columns
sl@0	2338	*/
sl@0	2339	if( pDest->eDest==SRT_Output ){
sl@0	2340	Select *pFirst = pPrior;
sl@0	2341	while( pFirst->pPrior ) pFirst = pFirst->pPrior;
sl@0	2342	generateColumnNames(pParse, 0, pFirst->pEList);
sl@0	2343	}
sl@0	2344
sl@0	2345	/* Reassembly the compound query so that it will be freed correctly
sl@0	2346	** by the calling function */
sl@0	2347	if( p->pPrior ){
sl@0	2348	sqlite3SelectDelete(db, p->pPrior);
sl@0	2349	}
sl@0	2350	p->pPrior = pPrior;
sl@0	2351
sl@0	2352	/*** TBD: Insert subroutine calls to close cursors on incomplete
sl@0	2353	** subqueries **/
sl@0	2354	return SQLITE_OK;
sl@0	2355	}
sl@0	2356	#endif
sl@0	2357
sl@0	2358	#if !defined(SQLITE_OMIT_SUBQUERY) \|\| !defined(SQLITE_OMIT_VIEW)
sl@0	2359	/* Forward Declarations */
sl@0	2360	static void substExprList(sqlite3, ExprList, int, ExprList*);
sl@0	2361	static void substSelect(sqlite3, Select , int, ExprList *);
sl@0	2362
sl@0	2363	/*
sl@0	2364	** Scan through the expression pExpr. Replace every reference to
sl@0	2365	** a column in table number iTable with a copy of the iColumn-th
sl@0	2366	** entry in pEList. (But leave references to the ROWID column
sl@0	2367	** unchanged.)
sl@0	2368	**
sl@0	2369	** This routine is part of the flattening procedure. A subquery
sl@0	2370	** whose result set is defined by pEList appears as entry in the
sl@0	2371	** FROM clause of a SELECT such that the VDBE cursor assigned to that
sl@0	2372	** FORM clause entry is iTable. This routine make the necessary
sl@0	2373	** changes to pExpr so that it refers directly to the source table
sl@0	2374	** of the subquery rather the result set of the subquery.
sl@0	2375	*/
sl@0	2376	static void substExpr(
sl@0	2377	sqlite3 db, / Report malloc errors to this connection */
sl@0	2378	Expr pExpr, / Expr in which substitution occurs */
sl@0	2379	int iTable, /* Table to be substituted */
sl@0	2380	ExprList pEList / Substitute expressions */
sl@0	2381	){
sl@0	2382	if( pExpr==0 ) return;
sl@0	2383	if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
sl@0	2384	if( pExpr->iColumn<0 ){
sl@0	2385	pExpr->op = TK_NULL;
sl@0	2386	}else{
sl@0	2387	Expr *pNew;
sl@0	2388	assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
sl@0	2389	assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
sl@0	2390	pNew = pEList->a[pExpr->iColumn].pExpr;
sl@0	2391	assert( pNew!=0 );
sl@0	2392	pExpr->op = pNew->op;
sl@0	2393	assert( pExpr->pLeft==0 );
sl@0	2394	pExpr->pLeft = sqlite3ExprDup(db, pNew->pLeft);
sl@0	2395	assert( pExpr->pRight==0 );
sl@0	2396	pExpr->pRight = sqlite3ExprDup(db, pNew->pRight);
sl@0	2397	assert( pExpr->pList==0 );
sl@0	2398	pExpr->pList = sqlite3ExprListDup(db, pNew->pList);
sl@0	2399	pExpr->iTable = pNew->iTable;
sl@0	2400	pExpr->pTab = pNew->pTab;
sl@0	2401	pExpr->iColumn = pNew->iColumn;
sl@0	2402	pExpr->iAgg = pNew->iAgg;
sl@0	2403	sqlite3TokenCopy(db, &pExpr->token, &pNew->token);
sl@0	2404	sqlite3TokenCopy(db, &pExpr->span, &pNew->span);
sl@0	2405	pExpr->pSelect = sqlite3SelectDup(db, pNew->pSelect);
sl@0	2406	pExpr->flags = pNew->flags;
sl@0	2407	}
sl@0	2408	}else{
sl@0	2409	substExpr(db, pExpr->pLeft, iTable, pEList);
sl@0	2410	substExpr(db, pExpr->pRight, iTable, pEList);
sl@0	2411	substSelect(db, pExpr->pSelect, iTable, pEList);
sl@0	2412	substExprList(db, pExpr->pList, iTable, pEList);
sl@0	2413	}
sl@0	2414	}
sl@0	2415	static void substExprList(
sl@0	2416	sqlite3 db, / Report malloc errors here */
sl@0	2417	ExprList pList, / List to scan and in which to make substitutes */
sl@0	2418	int iTable, /* Table to be substituted */
sl@0	2419	ExprList pEList / Substitute values */
sl@0	2420	){
sl@0	2421	int i;
sl@0	2422	if( pList==0 ) return;
sl@0	2423	for(i=0; i<pList->nExpr; i++){
sl@0	2424	substExpr(db, pList->a[i].pExpr, iTable, pEList);
sl@0	2425	}
sl@0	2426	}
sl@0	2427	static void substSelect(
sl@0	2428	sqlite3 db, / Report malloc errors here */
sl@0	2429	Select p, / SELECT statement in which to make substitutions */
sl@0	2430	int iTable, /* Table to be replaced */
sl@0	2431	ExprList pEList / Substitute values */
sl@0	2432	){
sl@0	2433	SrcList *pSrc;
sl@0	2434	struct SrcList_item *pItem;
sl@0	2435	int i;
sl@0	2436	if( !p ) return;
sl@0	2437	substExprList(db, p->pEList, iTable, pEList);
sl@0	2438	substExprList(db, p->pGroupBy, iTable, pEList);
sl@0	2439	substExprList(db, p->pOrderBy, iTable, pEList);
sl@0	2440	substExpr(db, p->pHaving, iTable, pEList);
sl@0	2441	substExpr(db, p->pWhere, iTable, pEList);
sl@0	2442	substSelect(db, p->pPrior, iTable, pEList);
sl@0	2443	pSrc = p->pSrc;
sl@0	2444	if( pSrc ){
sl@0	2445	for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
sl@0	2446	substSelect(db, pItem->pSelect, iTable, pEList);
sl@0	2447	}
sl@0	2448	}
sl@0	2449	}
sl@0	2450	#endif /* !defined(SQLITE_OMIT_SUBQUERY) \|\| !defined(SQLITE_OMIT_VIEW) */
sl@0	2451
sl@0	2452	#if !defined(SQLITE_OMIT_SUBQUERY) \|\| !defined(SQLITE_OMIT_VIEW)
sl@0	2453	/*
sl@0	2454	** This routine attempts to flatten subqueries in order to speed
sl@0	2455	** execution. It returns 1 if it makes changes and 0 if no flattening
sl@0	2456	** occurs.
sl@0	2457	**
sl@0	2458	** To understand the concept of flattening, consider the following
sl@0	2459	** query:
sl@0	2460	**
sl@0	2461	** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
sl@0	2462	**
sl@0	2463	** The default way of implementing this query is to execute the
sl@0	2464	** subquery first and store the results in a temporary table, then
sl@0	2465	** run the outer query on that temporary table. This requires two
sl@0	2466	** passes over the data. Furthermore, because the temporary table
sl@0	2467	** has no indices, the WHERE clause on the outer query cannot be
sl@0	2468	** optimized.
sl@0	2469	**
sl@0	2470	** This routine attempts to rewrite queries such as the above into
sl@0	2471	** a single flat select, like this:
sl@0	2472	**
sl@0	2473	** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
sl@0	2474	**
sl@0	2475	** The code generated for this simpification gives the same result
sl@0	2476	** but only has to scan the data once. And because indices might
sl@0	2477	** exist on the table t1, a complete scan of the data might be
sl@0	2478	** avoided.
sl@0	2479	**
sl@0	2480	** Flattening is only attempted if all of the following are true:
sl@0	2481	**
sl@0	2482	** (1) The subquery and the outer query do not both use aggregates.
sl@0	2483	**
sl@0	2484	** (2) The subquery is not an aggregate or the outer query is not a join.
sl@0	2485	**
sl@0	2486	** (3) The subquery is not the right operand of a left outer join
sl@0	2487	** (Originally ticket #306. Strenghtened by ticket #3300)
sl@0	2488	**
sl@0	2489	** (4) The subquery is not DISTINCT or the outer query is not a join.
sl@0	2490	**
sl@0	2491	** (5) The subquery is not DISTINCT or the outer query does not use
sl@0	2492	** aggregates.
sl@0	2493	**
sl@0	2494	** (6) The subquery does not use aggregates or the outer query is not
sl@0	2495	** DISTINCT.
sl@0	2496	**
sl@0	2497	** (7) The subquery has a FROM clause.
sl@0	2498	**
sl@0	2499	** (8) The subquery does not use LIMIT or the outer query is not a join.
sl@0	2500	**
sl@0	2501	** (9) The subquery does not use LIMIT or the outer query does not use
sl@0	2502	** aggregates.
sl@0	2503	**
sl@0	2504	** (10) The subquery does not use aggregates or the outer query does not
sl@0	2505	** use LIMIT.
sl@0	2506	**
sl@0	2507	** (11) The subquery and the outer query do not both have ORDER BY clauses.
sl@0	2508	**
sl@0	2509	** (12) Not implemented. Subsumed into restriction (3). Was previously
sl@0	2510	** a separate restriction deriving from ticket #350.
sl@0	2511	**
sl@0	2512	** (13) The subquery and outer query do not both use LIMIT
sl@0	2513	**
sl@0	2514	** (14) The subquery does not use OFFSET
sl@0	2515	**
sl@0	2516	** (15) The outer query is not part of a compound select or the
sl@0	2517	** subquery does not have both an ORDER BY and a LIMIT clause.
sl@0	2518	** (See ticket #2339)
sl@0	2519	**
sl@0	2520	** (16) The outer query is not an aggregate or the subquery does
sl@0	2521	** not contain ORDER BY. (Ticket #2942) This used to not matter
sl@0	2522	** until we introduced the group_concat() function.
sl@0	2523	**
sl@0	2524	** (17) The sub-query is not a compound select, or it is a UNION ALL
sl@0	2525	** compound clause made up entirely of non-aggregate queries, and
sl@0	2526	** the parent query:
sl@0	2527	**
sl@0	2528	** * is not itself part of a compound select,
sl@0	2529	** * is not an aggregate or DISTINCT query, and
sl@0	2530	** * has no other tables or sub-selects in the FROM clause.
sl@0	2531	**
sl@0	2532	** The parent and sub-query may contain WHERE clauses. Subject to
sl@0	2533	** rules (11), (13) and (14), they may also contain ORDER BY,
sl@0	2534	** LIMIT and OFFSET clauses.
sl@0	2535	**
sl@0	2536	** (18) If the sub-query is a compound select, then all terms of the
sl@0	2537	** ORDER by clause of the parent must be simple references to
sl@0	2538	** columns of the sub-query.
sl@0	2539	**
sl@0	2540	** (19) The subquery does not use LIMIT or the outer query does not
sl@0	2541	** have a WHERE clause.
sl@0	2542	**
sl@0	2543	** In this routine, the "p" parameter is a pointer to the outer query.
sl@0	2544	** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
sl@0	2545	** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
sl@0	2546	**
sl@0	2547	** If flattening is not attempted, this routine is a no-op and returns 0.
sl@0	2548	** If flattening is attempted this routine returns 1.
sl@0	2549	**
sl@0	2550	** All of the expression analysis must occur on both the outer query and
sl@0	2551	** the subquery before this routine runs.
sl@0	2552	*/
sl@0	2553	static int flattenSubquery(
sl@0	2554	Parse pParse, / Parsing context */
sl@0	2555	Select p, / The parent or outer SELECT statement */
sl@0	2556	int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
sl@0	2557	int isAgg, /* True if outer SELECT uses aggregate functions */
sl@0	2558	int subqueryIsAgg /* True if the subquery uses aggregate functions */
sl@0	2559	){
sl@0	2560	const char *zSavedAuthContext = pParse->zAuthContext;
sl@0	2561	Select *pParent;
sl@0	2562	Select pSub; / The inner query or "subquery" */
sl@0	2563	Select pSub1; / Pointer to the rightmost select in sub-query */
sl@0	2564	SrcList pSrc; / The FROM clause of the outer query */
sl@0	2565	SrcList pSubSrc; / The FROM clause of the subquery */
sl@0	2566	ExprList pList; / The result set of the outer query */
sl@0	2567	int iParent; /* VDBE cursor number of the pSub result set temp table */
sl@0	2568	int i; /* Loop counter */
sl@0	2569	Expr pWhere; / The WHERE clause */
sl@0	2570	struct SrcList_item pSubitem; / The subquery */
sl@0	2571	sqlite3 *db = pParse->db;
sl@0	2572
sl@0	2573	/* Check to see if flattening is permitted. Return 0 if not.
sl@0	2574	*/
sl@0	2575	if( p==0 ) return 0;
sl@0	2576	pSrc = p->pSrc;
sl@0	2577	assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
sl@0	2578	pSubitem = &pSrc->a[iFrom];
sl@0	2579	iParent = pSubitem->iCursor;
sl@0	2580	pSub = pSubitem->pSelect;
sl@0	2581	assert( pSub!=0 );
sl@0	2582	if( isAgg && subqueryIsAgg ) return 0; /* Restriction (1) */
sl@0	2583	if( subqueryIsAgg && pSrc->nSrc>1 ) return 0; /* Restriction (2) */
sl@0	2584	pSubSrc = pSub->pSrc;
sl@0	2585	assert( pSubSrc );
sl@0	2586	/* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
sl@0	2587	** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
sl@0	2588	** because they could be computed at compile-time. But when LIMIT and OFFSET
sl@0	2589	** became arbitrary expressions, we were forced to add restrictions (13)
sl@0	2590	** and (14). */
sl@0	2591	if( pSub->pLimit && p->pLimit ) return 0; /* Restriction (13) */
sl@0	2592	if( pSub->pOffset ) return 0; /* Restriction (14) */
sl@0	2593	if( p->pRightmost && pSub->pLimit && pSub->pOrderBy ){
sl@0	2594	return 0; /* Restriction (15) */
sl@0	2595	}
sl@0	2596	if( pSubSrc->nSrc==0 ) return 0; /* Restriction (7) */
sl@0	2597	if( ((pSub->selFlags & SF_Distinct)!=0 \|\| pSub->pLimit)
sl@0	2598	&& (pSrc->nSrc>1 \|\| isAgg) ){ /* Restrictions (4)(5)(8)(9) */
sl@0	2599	return 0;
sl@0	2600	}
sl@0	2601	if( (p->selFlags & SF_Distinct)!=0 && subqueryIsAgg ){
sl@0	2602	return 0; /* Restriction (6) */
sl@0	2603	}
sl@0	2604	if( p->pOrderBy && pSub->pOrderBy ){
sl@0	2605	return 0; /* Restriction (11) */
sl@0	2606	}
sl@0	2607	if( isAgg && pSub->pOrderBy ) return 0; /* Restriction (16) */
sl@0	2608	if( pSub->pLimit && p->pWhere ) return 0; /* Restriction (19) */
sl@0	2609
sl@0	2610	/* OBSOLETE COMMENT 1:
sl@0	2611	** Restriction 3: If the subquery is a join, make sure the subquery is
sl@0	2612	** not used as the right operand of an outer join. Examples of why this
sl@0	2613	** is not allowed:
sl@0	2614	**
sl@0	2615	** t1 LEFT OUTER JOIN (t2 JOIN t3)
sl@0	2616	**
sl@0	2617	** If we flatten the above, we would get
sl@0	2618	**
sl@0	2619	** (t1 LEFT OUTER JOIN t2) JOIN t3
sl@0	2620	**
sl@0	2621	** which is not at all the same thing.
sl@0	2622	**
sl@0	2623	** OBSOLETE COMMENT 2:
sl@0	2624	** Restriction 12: If the subquery is the right operand of a left outer
sl@0	2625	** join, make sure the subquery has no WHERE clause.
sl@0	2626	** An examples of why this is not allowed:
sl@0	2627	**
sl@0	2628	** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
sl@0	2629	**
sl@0	2630	** If we flatten the above, we would get
sl@0	2631	**
sl@0	2632	** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
sl@0	2633	**
sl@0	2634	** But the t2.x>0 test will always fail on a NULL row of t2, which
sl@0	2635	** effectively converts the OUTER JOIN into an INNER JOIN.
sl@0	2636	**
sl@0	2637	** THIS OVERRIDES OBSOLETE COMMENTS 1 AND 2 ABOVE:
sl@0	2638	** Ticket #3300 shows that flattening the right term of a LEFT JOIN
sl@0	2639	** is fraught with danger. Best to avoid the whole thing. If the
sl@0	2640	** subquery is the right term of a LEFT JOIN, then do not flatten.
sl@0	2641	*/
sl@0	2642	if( (pSubitem->jointype & JT_OUTER)!=0 ){
sl@0	2643	return 0;
sl@0	2644	}
sl@0	2645
sl@0	2646	/* Restriction 17: If the sub-query is a compound SELECT, then it must
sl@0	2647	** use only the UNION ALL operator. And none of the simple select queries
sl@0	2648	** that make up the compound SELECT are allowed to be aggregate or distinct
sl@0	2649	** queries.
sl@0	2650	*/
sl@0	2651	if( pSub->pPrior ){
sl@0	2652	if( p->pPrior \|\| isAgg \|\| (p->selFlags & SF_Distinct)!=0 \|\| pSrc->nSrc!=1 ){
sl@0	2653	return 0;
sl@0	2654	}
sl@0	2655	for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
sl@0	2656	if( (pSub1->selFlags & (SF_Distinct\|SF_Aggregate))!=0
sl@0	2657	\|\| (pSub1->pPrior && pSub1->op!=TK_ALL)
sl@0	2658	\|\| !pSub1->pSrc \|\| pSub1->pSrc->nSrc!=1
sl@0	2659	){
sl@0	2660	return 0;
sl@0	2661	}
sl@0	2662	}
sl@0	2663
sl@0	2664	/* Restriction 18. */
sl@0	2665	if( p->pOrderBy ){
sl@0	2666	int ii;
sl@0	2667	for(ii=0; ii<p->pOrderBy->nExpr; ii++){
sl@0	2668	if( p->pOrderBy->a[ii].iCol==0 ) return 0;
sl@0	2669	}
sl@0	2670	}
sl@0	2671	}
sl@0	2672
sl@0	2673	/*** If we reach this point, flattening is permitted. ***/
sl@0	2674
sl@0	2675	/* Authorize the subquery */
sl@0	2676	pParse->zAuthContext = pSubitem->zName;
sl@0	2677	sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
sl@0	2678	pParse->zAuthContext = zSavedAuthContext;
sl@0	2679
sl@0	2680	/* If the sub-query is a compound SELECT statement, then (by restrictions
sl@0	2681	** 17 and 18 above) it must be a UNION ALL and the parent query must
sl@0	2682	** be of the form:
sl@0	2683	**
sl@0	2684	** SELECT <expr-list> FROM (<sub-query>) <where-clause>
sl@0	2685	**
sl@0	2686	** followed by any ORDER BY, LIMIT and/or OFFSET clauses. This block
sl@0	2687	** creates N copies of the parent query without any ORDER BY, LIMIT or
sl@0	2688	** OFFSET clauses and joins them to the left-hand-side of the original
sl@0	2689	** using UNION ALL operators. In this case N is the number of simple
sl@0	2690	** select statements in the compound sub-query.
sl@0	2691	*/
sl@0	2692	for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){
sl@0	2693	Select *pNew;
sl@0	2694	ExprList *pOrderBy = p->pOrderBy;
sl@0	2695	Expr *pLimit = p->pLimit;
sl@0	2696	Expr *pOffset = p->pOffset;
sl@0	2697	Select *pPrior = p->pPrior;
sl@0	2698	p->pOrderBy = 0;
sl@0	2699	p->pSrc = 0;
sl@0	2700	p->pPrior = 0;
sl@0	2701	p->pLimit = 0;
sl@0	2702	pNew = sqlite3SelectDup(db, p);
sl@0	2703	pNew->pPrior = pPrior;
sl@0	2704	p->pPrior = pNew;
sl@0	2705	p->pOrderBy = pOrderBy;
sl@0	2706	p->op = TK_ALL;
sl@0	2707	p->pSrc = pSrc;
sl@0	2708	p->pLimit = pLimit;
sl@0	2709	p->pOffset = pOffset;
sl@0	2710	p->pRightmost = 0;
sl@0	2711	pNew->pRightmost = 0;
sl@0	2712	}
sl@0	2713
sl@0	2714	/* Begin flattening the iFrom-th entry of the FROM clause
sl@0	2715	** in the outer query.
sl@0	2716	*/
sl@0	2717	pSub = pSub1 = pSubitem->pSelect;
sl@0	2718	for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
sl@0	2719	int nSubSrc = pSubSrc->nSrc;
sl@0	2720	int jointype = 0;
sl@0	2721	pSubSrc = pSub->pSrc;
sl@0	2722	pSrc = pParent->pSrc;
sl@0	2723
sl@0	2724	/* Move all of the FROM elements of the subquery into the
sl@0	2725	** the FROM clause of the outer query. Before doing this, remember
sl@0	2726	** the cursor number for the original outer query FROM element in
sl@0	2727	** iParent. The iParent cursor will never be used. Subsequent code
sl@0	2728	** will scan expressions looking for iParent references and replace
sl@0	2729	** those references with expressions that resolve to the subquery FROM
sl@0	2730	** elements we are now copying in.
sl@0	2731	*/
sl@0	2732	if( pSrc ){
sl@0	2733	Table *pTabToDel;
sl@0	2734	pSubitem = &pSrc->a[iFrom];
sl@0	2735	nSubSrc = pSubSrc->nSrc;
sl@0	2736	jointype = pSubitem->jointype;
sl@0	2737	sqlite3DbFree(db, pSubitem->zDatabase);
sl@0	2738	sqlite3DbFree(db, pSubitem->zName);
sl@0	2739	sqlite3DbFree(db, pSubitem->zAlias);
sl@0	2740	pSubitem->zDatabase = 0;
sl@0	2741	pSubitem->zName = 0;
sl@0	2742	pSubitem->zAlias = 0;
sl@0	2743
sl@0	2744	/* If the FROM element is a subquery, defer deleting the Table
sl@0	2745	** object associated with that subquery until code generation is
sl@0	2746	** complete, since there may still exist Expr.pTab entires that
sl@0	2747	** refer to the subquery even after flattening. Ticket #3346.
sl@0	2748	*/
sl@0	2749	if( (pTabToDel = pSubitem->pTab)!=0 ){
sl@0	2750	if( pTabToDel->nRef==1 ){
sl@0	2751	pTabToDel->pNextZombie = pParse->pZombieTab;
sl@0	2752	pParse->pZombieTab = pTabToDel;
sl@0	2753	}else{
sl@0	2754	pTabToDel->nRef--;
sl@0	2755	}
sl@0	2756	}
sl@0	2757	pSubitem->pTab = 0;
sl@0	2758	}
sl@0	2759	if( nSubSrc!=1 \|\| !pSrc ){
sl@0	2760	int extra = nSubSrc - 1;
sl@0	2761	for(i=(pSrc?1:0); i<nSubSrc; i++){
sl@0	2762	pSrc = sqlite3SrcListAppend(db, pSrc, 0, 0);
sl@0	2763	if( pSrc==0 ){
sl@0	2764	pParent->pSrc = 0;
sl@0	2765	return 1;
sl@0	2766	}
sl@0	2767	}
sl@0	2768	pParent->pSrc = pSrc;
sl@0	2769	for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
sl@0	2770	pSrc->a[i] = pSrc->a[i-extra];
sl@0	2771	}
sl@0	2772	}
sl@0	2773	for(i=0; i<nSubSrc; i++){
sl@0	2774	pSrc->a[i+iFrom] = pSubSrc->a[i];
sl@0	2775	memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
sl@0	2776	}
sl@0	2777	pSrc->a[iFrom].jointype = jointype;
sl@0	2778
sl@0	2779	/* Now begin substituting subquery result set expressions for
sl@0	2780	** references to the iParent in the outer query.
sl@0	2781	**
sl@0	2782	** Example:
sl@0	2783	**
sl@0	2784	** SELECT a+5, b10 FROM (SELECT x3 AS a, y+10 AS b FROM t1) WHERE a>b;
sl@0	2785	** \ \_____________ subquery __________/ /
sl@0	2786	** \_____________________ outer query ______________________________/
sl@0	2787	**
sl@0	2788	** We look at every expression in the outer query and every place we see
sl@0	2789	** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
sl@0	2790	*/
sl@0	2791	pList = pParent->pEList;
sl@0	2792	for(i=0; i<pList->nExpr; i++){
sl@0	2793	Expr *pExpr;
sl@0	2794	if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
sl@0	2795	pList->a[i].zName =
sl@0	2796	sqlite3DbStrNDup(db, (char*)pExpr->span.z, pExpr->span.n);
sl@0	2797	}
sl@0	2798	}
sl@0	2799	substExprList(db, pParent->pEList, iParent, pSub->pEList);
sl@0	2800	if( isAgg ){
sl@0	2801	substExprList(db, pParent->pGroupBy, iParent, pSub->pEList);
sl@0	2802	substExpr(db, pParent->pHaving, iParent, pSub->pEList);
sl@0	2803	}
sl@0	2804	if( pSub->pOrderBy ){
sl@0	2805	assert( pParent->pOrderBy==0 );
sl@0	2806	pParent->pOrderBy = pSub->pOrderBy;
sl@0	2807	pSub->pOrderBy = 0;
sl@0	2808	}else if( pParent->pOrderBy ){
sl@0	2809	substExprList(db, pParent->pOrderBy, iParent, pSub->pEList);
sl@0	2810	}
sl@0	2811	if( pSub->pWhere ){
sl@0	2812	pWhere = sqlite3ExprDup(db, pSub->pWhere);
sl@0	2813	}else{
sl@0	2814	pWhere = 0;
sl@0	2815	}
sl@0	2816	if( subqueryIsAgg ){
sl@0	2817	assert( pParent->pHaving==0 );
sl@0	2818	pParent->pHaving = pParent->pWhere;
sl@0	2819	pParent->pWhere = pWhere;
sl@0	2820	substExpr(db, pParent->pHaving, iParent, pSub->pEList);
sl@0	2821	pParent->pHaving = sqlite3ExprAnd(db, pParent->pHaving,
sl@0	2822	sqlite3ExprDup(db, pSub->pHaving));
sl@0	2823	assert( pParent->pGroupBy==0 );
sl@0	2824	pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy);
sl@0	2825	}else{
sl@0	2826	substExpr(db, pParent->pWhere, iParent, pSub->pEList);
sl@0	2827	pParent->pWhere = sqlite3ExprAnd(db, pParent->pWhere, pWhere);
sl@0	2828	}
sl@0	2829
sl@0	2830	/* The flattened query is distinct if either the inner or the
sl@0	2831	** outer query is distinct.
sl@0	2832	*/
sl@0	2833	pParent->selFlags \|= pSub->selFlags & SF_Distinct;
sl@0	2834
sl@0	2835	/*
sl@0	2836	** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
sl@0	2837	**
sl@0	2838	** One is tempted to try to add a and b to combine the limits. But this
sl@0	2839	** does not work if either limit is negative.
sl@0	2840	*/
sl@0	2841	if( pSub->pLimit ){
sl@0	2842	pParent->pLimit = pSub->pLimit;
sl@0	2843	pSub->pLimit = 0;
sl@0	2844	}
sl@0	2845	}
sl@0	2846
sl@0	2847	/* Finially, delete what is left of the subquery and return
sl@0	2848	** success.
sl@0	2849	*/
sl@0	2850	sqlite3SelectDelete(db, pSub1);
sl@0	2851
sl@0	2852	return 1;
sl@0	2853	}
sl@0	2854	#endif /* !defined(SQLITE_OMIT_SUBQUERY) \|\| !defined(SQLITE_OMIT_VIEW) */
sl@0	2855
sl@0	2856	/*
sl@0	2857	** Analyze the SELECT statement passed as an argument to see if it
sl@0	2858	** is a min() or max() query. Return WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX if
sl@0	2859	** it is, or 0 otherwise. At present, a query is considered to be
sl@0	2860	** a min()/max() query if:
sl@0	2861	**
sl@0	2862	** 1. There is a single object in the FROM clause.
sl@0	2863	**
sl@0	2864	** 2. There is a single expression in the result set, and it is
sl@0	2865	** either min(x) or max(x), where x is a column reference.
sl@0	2866	*/
sl@0	2867	static int minMaxQuery(Parse pParse, Select p){
sl@0	2868	Expr *pExpr;
sl@0	2869	ExprList *pEList = p->pEList;
sl@0	2870
sl@0	2871	if( pEList->nExpr!=1 ) return WHERE_ORDERBY_NORMAL;
sl@0	2872	pExpr = pEList->a[0].pExpr;
sl@0	2873	pEList = pExpr->pList;
sl@0	2874	if( pExpr->op!=TK_AGG_FUNCTION \|\| pEList==0 \|\| pEList->nExpr!=1 ) return 0;
sl@0	2875	if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return WHERE_ORDERBY_NORMAL;
sl@0	2876	if( pExpr->token.n!=3 ) return WHERE_ORDERBY_NORMAL;
sl@0	2877	if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
sl@0	2878	return WHERE_ORDERBY_MIN;
sl@0	2879	}else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
sl@0	2880	return WHERE_ORDERBY_MAX;
sl@0	2881	}
sl@0	2882	return WHERE_ORDERBY_NORMAL;
sl@0	2883	}
sl@0	2884
sl@0	2885	/*
sl@0	2886	** If the source-list item passed as an argument was augmented with an
sl@0	2887	** INDEXED BY clause, then try to locate the specified index. If there
sl@0	2888	** was such a clause and the named index cannot be found, return
sl@0	2889	** SQLITE_ERROR and leave an error in pParse. Otherwise, populate
sl@0	2890	** pFrom->pIndex and return SQLITE_OK.
sl@0	2891	*/
sl@0	2892	int sqlite3IndexedByLookup(Parse pParse, struct SrcList_item pFrom){
sl@0	2893	if( pFrom->pTab && pFrom->zIndex ){
sl@0	2894	Table *pTab = pFrom->pTab;
sl@0	2895	char *zIndex = pFrom->zIndex;
sl@0	2896	Index *pIdx;
sl@0	2897	for(pIdx=pTab->pIndex;
sl@0	2898	pIdx && sqlite3StrICmp(pIdx->zName, zIndex);
sl@0	2899	pIdx=pIdx->pNext
sl@0	2900	);
sl@0	2901	if( !pIdx ){
sl@0	2902	sqlite3ErrorMsg(pParse, "no such index: %s", zIndex, 0);
sl@0	2903	return SQLITE_ERROR;
sl@0	2904	}
sl@0	2905	pFrom->pIndex = pIdx;
sl@0	2906	}
sl@0	2907	return SQLITE_OK;
sl@0	2908	}
sl@0	2909
sl@0	2910	/*
sl@0	2911	** This routine is a Walker callback for "expanding" a SELECT statement.
sl@0	2912	** "Expanding" means to do the following:
sl@0	2913	**
sl@0	2914	** (1) Make sure VDBE cursor numbers have been assigned to every
sl@0	2915	** element of the FROM clause.
sl@0	2916	**
sl@0	2917	** (2) Fill in the pTabList->a[].pTab fields in the SrcList that
sl@0	2918	** defines FROM clause. When views appear in the FROM clause,
sl@0	2919	** fill pTabList->a[].pSelect with a copy of the SELECT statement
sl@0	2920	** that implements the view. A copy is made of the view's SELECT
sl@0	2921	** statement so that we can freely modify or delete that statement
sl@0	2922	** without worrying about messing up the presistent representation
sl@0	2923	** of the view.
sl@0	2924	**
sl@0	2925	** (3) Add terms to the WHERE clause to accomodate the NATURAL keyword
sl@0	2926	** on joins and the ON and USING clause of joins.
sl@0	2927	**
sl@0	2928	** (4) Scan the list of columns in the result set (pEList) looking
sl@0	2929	** for instances of the "" operator or the TABLE. operator.
sl@0	2930	** If found, expand each "*" to be every column in every table
sl@0	2931	** and TABLE.* to be every column in TABLE.
sl@0	2932	**
sl@0	2933	*/
sl@0	2934	static int selectExpander(Walker pWalker, Select p){
sl@0	2935	Parse *pParse = pWalker->pParse;
sl@0	2936	int i, j, k;
sl@0	2937	SrcList *pTabList;
sl@0	2938	ExprList *pEList;
sl@0	2939	struct SrcList_item *pFrom;
sl@0	2940	sqlite3 *db = pParse->db;
sl@0	2941
sl@0	2942	if( db->mallocFailed ){
sl@0	2943	return WRC_Abort;
sl@0	2944	}
sl@0	2945	if( p->pSrc==0 \|\| (p->selFlags & SF_Expanded)!=0 ){
sl@0	2946	return WRC_Prune;
sl@0	2947	}
sl@0	2948	p->selFlags \|= SF_Expanded;
sl@0	2949	pTabList = p->pSrc;
sl@0	2950	pEList = p->pEList;
sl@0	2951
sl@0	2952	/* Make sure cursor numbers have been assigned to all entries in
sl@0	2953	** the FROM clause of the SELECT statement.
sl@0	2954	*/
sl@0	2955	sqlite3SrcListAssignCursors(pParse, pTabList);
sl@0	2956
sl@0	2957	/* Look up every table named in the FROM clause of the select. If
sl@0	2958	** an entry of the FROM clause is a subquery instead of a table or view,
sl@0	2959	** then create a transient table structure to describe the subquery.
sl@0	2960	*/
sl@0	2961	for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
sl@0	2962	Table *pTab;
sl@0	2963	if( pFrom->pTab!=0 ){
sl@0	2964	/* This statement has already been prepared. There is no need
sl@0	2965	** to go further. */
sl@0	2966	assert( i==0 );
sl@0	2967	return WRC_Prune;
sl@0	2968	}
sl@0	2969	if( pFrom->zName==0 ){
sl@0	2970	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	2971	Select *pSel = pFrom->pSelect;
sl@0	2972	/* A sub-query in the FROM clause of a SELECT */
sl@0	2973	assert( pSel!=0 );
sl@0	2974	assert( pFrom->pTab==0 );
sl@0	2975	sqlite3WalkSelect(pWalker, pSel);
sl@0	2976	pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
sl@0	2977	if( pTab==0 ) return WRC_Abort;
sl@0	2978	pTab->db = db;
sl@0	2979	pTab->nRef = 1;
sl@0	2980	pTab->zName = sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pTab);
sl@0	2981	while( pSel->pPrior ){ pSel = pSel->pPrior; }
sl@0	2982	selectColumnsFromExprList(pParse, pSel->pEList, &pTab->nCol, &pTab->aCol);
sl@0	2983	pTab->iPKey = -1;
sl@0	2984	pTab->tabFlags \|= TF_Ephemeral;
sl@0	2985	#endif
sl@0	2986	}else{
sl@0	2987	/* An ordinary table or view name in the FROM clause */
sl@0	2988	assert( pFrom->pTab==0 );
sl@0	2989	pFrom->pTab = pTab =
sl@0	2990	sqlite3LocateTable(pParse,0,pFrom->zName,pFrom->zDatabase);
sl@0	2991	if( pTab==0 ) return WRC_Abort;
sl@0	2992	pTab->nRef++;
sl@0	2993	#if !defined(SQLITE_OMIT_VIEW) \|\| !defined (SQLITE_OMIT_VIRTUALTABLE)
sl@0	2994	if( pTab->pSelect \|\| IsVirtual(pTab) ){
sl@0	2995	/* We reach here if the named table is a really a view */
sl@0	2996	if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
sl@0	2997
sl@0	2998	/* If pFrom->pSelect!=0 it means we are dealing with a
sl@0	2999	** view within a view. The SELECT structure has already been
sl@0	3000	** copied by the outer view so we can skip the copy step here
sl@0	3001	** in the inner view.
sl@0	3002	*/
sl@0	3003	if( pFrom->pSelect==0 ){
sl@0	3004	pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect);
sl@0	3005	sqlite3WalkSelect(pWalker, pFrom->pSelect);
sl@0	3006	}
sl@0	3007	}
sl@0	3008	#endif
sl@0	3009	}
sl@0	3010
sl@0	3011	/* Locate the index named by the INDEXED BY clause, if any. */
sl@0	3012	if( sqlite3IndexedByLookup(pParse, pFrom) ){
sl@0	3013	return WRC_Abort;
sl@0	3014	}
sl@0	3015	}
sl@0	3016
sl@0	3017	/* Process NATURAL keywords, and ON and USING clauses of joins.
sl@0	3018	*/
sl@0	3019	if( db->mallocFailed \|\| sqliteProcessJoin(pParse, p) ){
sl@0	3020	return WRC_Abort;
sl@0	3021	}
sl@0	3022
sl@0	3023	/* For every "*" that occurs in the column list, insert the names of
sl@0	3024	** all columns in all tables. And for every TABLE.* insert the names
sl@0	3025	** of all columns in TABLE. The parser inserted a special expression
sl@0	3026	** with the TK_ALL operator for each "*" that it found in the column list.
sl@0	3027	** The following code just has to locate the TK_ALL expressions and expand
sl@0	3028	** each one to the list of all columns in all tables.
sl@0	3029	**
sl@0	3030	** The first loop just checks to see if there are any "*" operators
sl@0	3031	** that need expanding.
sl@0	3032	*/
sl@0	3033	for(k=0; k<pEList->nExpr; k++){
sl@0	3034	Expr *pE = pEList->a[k].pExpr;
sl@0	3035	if( pE->op==TK_ALL ) break;
sl@0	3036	if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
sl@0	3037	&& pE->pLeft && pE->pLeft->op==TK_ID ) break;
sl@0	3038	}
sl@0	3039	if( k<pEList->nExpr ){
sl@0	3040	/*
sl@0	3041	** If we get here it means the result set contains one or more "*"
sl@0	3042	** operators that need to be expanded. Loop through each expression
sl@0	3043	** in the result set and expand them one by one.
sl@0	3044	*/
sl@0	3045	struct ExprList_item *a = pEList->a;
sl@0	3046	ExprList *pNew = 0;
sl@0	3047	int flags = pParse->db->flags;
sl@0	3048	int longNames = (flags & SQLITE_FullColNames)!=0
sl@0	3049	&& (flags & SQLITE_ShortColNames)==0;
sl@0	3050
sl@0	3051	for(k=0; k<pEList->nExpr; k++){
sl@0	3052	Expr *pE = a[k].pExpr;
sl@0	3053	if( pE->op!=TK_ALL &&
sl@0	3054	(pE->op!=TK_DOT \|\| pE->pRight==0 \|\| pE->pRight->op!=TK_ALL) ){
sl@0	3055	/* This particular expression does not need to be expanded.
sl@0	3056	*/
sl@0	3057	pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr, 0);
sl@0	3058	if( pNew ){
sl@0	3059	pNew->a[pNew->nExpr-1].zName = a[k].zName;
sl@0	3060	}
sl@0	3061	a[k].pExpr = 0;
sl@0	3062	a[k].zName = 0;
sl@0	3063	}else{
sl@0	3064	/* This expression is a "" or a "TABLE." and needs to be
sl@0	3065	** expanded. */
sl@0	3066	int tableSeen = 0; /* Set to 1 when TABLE matches */
sl@0	3067	char zTName; / text of name of TABLE */
sl@0	3068	if( pE->op==TK_DOT && pE->pLeft ){
sl@0	3069	zTName = sqlite3NameFromToken(db, &pE->pLeft->token);
sl@0	3070	}else{
sl@0	3071	zTName = 0;
sl@0	3072	}
sl@0	3073	for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
sl@0	3074	Table *pTab = pFrom->pTab;
sl@0	3075	char *zTabName = pFrom->zAlias;
sl@0	3076	if( zTabName==0 \|\| zTabName[0]==0 ){
sl@0	3077	zTabName = pTab->zName;
sl@0	3078	}
sl@0	3079	if( db->mallocFailed ) break;
sl@0	3080	if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
sl@0	3081	continue;
sl@0	3082	}
sl@0	3083	tableSeen = 1;
sl@0	3084	for(j=0; j<pTab->nCol; j++){
sl@0	3085	Expr pExpr, pRight;
sl@0	3086	char *zName = pTab->aCol[j].zName;
sl@0	3087
sl@0	3088	/* If a column is marked as 'hidden' (currently only possible
sl@0	3089	** for virtual tables), do not include it in the expanded
sl@0	3090	** result-set list.
sl@0	3091	*/
sl@0	3092	if( IsHiddenColumn(&pTab->aCol[j]) ){
sl@0	3093	assert(IsVirtual(pTab));
sl@0	3094	continue;
sl@0	3095	}
sl@0	3096
sl@0	3097	if( i>0 ){
sl@0	3098	struct SrcList_item *pLeft = &pTabList->a[i-1];
sl@0	3099	if( (pLeft[1].jointype & JT_NATURAL)!=0 &&
sl@0	3100	columnIndex(pLeft->pTab, zName)>=0 ){
sl@0	3101	/* In a NATURAL join, omit the join columns from the
sl@0	3102	** table on the right */
sl@0	3103	continue;
sl@0	3104	}
sl@0	3105	if( sqlite3IdListIndex(pLeft[1].pUsing, zName)>=0 ){
sl@0	3106	/* In a join with a USING clause, omit columns in the
sl@0	3107	** using clause from the table on the right. */
sl@0	3108	continue;
sl@0	3109	}
sl@0	3110	}
sl@0	3111	pRight = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
sl@0	3112	if( pRight==0 ) break;
sl@0	3113	setQuotedToken(pParse, &pRight->token, zName);
sl@0	3114	if( longNames \|\| pTabList->nSrc>1 ){
sl@0	3115	Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
sl@0	3116	pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
sl@0	3117	if( pExpr==0 ) break;
sl@0	3118	setQuotedToken(pParse, &pLeft->token, zTabName);
sl@0	3119	setToken(&pExpr->span,
sl@0	3120	sqlite3MPrintf(db, "%s.%s", zTabName, zName));
sl@0	3121	pExpr->span.dyn = 1;
sl@0	3122	pExpr->token.z = 0;
sl@0	3123	pExpr->token.n = 0;
sl@0	3124	pExpr->token.dyn = 0;
sl@0	3125	}else{
sl@0	3126	pExpr = pRight;
sl@0	3127	pExpr->span = pExpr->token;
sl@0	3128	pExpr->span.dyn = 0;
sl@0	3129	}
sl@0	3130	if( longNames ){
sl@0	3131	pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pExpr->span);
sl@0	3132	}else{
sl@0	3133	pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pRight->token);
sl@0	3134	}
sl@0	3135	}
sl@0	3136	}
sl@0	3137	if( !tableSeen ){
sl@0	3138	if( zTName ){
sl@0	3139	sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
sl@0	3140	}else{
sl@0	3141	sqlite3ErrorMsg(pParse, "no tables specified");
sl@0	3142	}
sl@0	3143	}
sl@0	3144	sqlite3DbFree(db, zTName);
sl@0	3145	}
sl@0	3146	}
sl@0	3147	sqlite3ExprListDelete(db, pEList);
sl@0	3148	p->pEList = pNew;
sl@0	3149	}
sl@0	3150	#if SQLITE_MAX_COLUMN
sl@0	3151	if( p->pEList && p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
sl@0	3152	sqlite3ErrorMsg(pParse, "too many columns in result set");
sl@0	3153	}
sl@0	3154	#endif
sl@0	3155	return WRC_Continue;
sl@0	3156	}
sl@0	3157
sl@0	3158	/*
sl@0	3159	** No-op routine for the parse-tree walker.
sl@0	3160	**
sl@0	3161	** When this routine is the Walker.xExprCallback then expression trees
sl@0	3162	** are walked without any actions being taken at each node. Presumably,
sl@0	3163	** when this routine is used for Walker.xExprCallback then
sl@0	3164	** Walker.xSelectCallback is set to do something useful for every
sl@0	3165	** subquery in the parser tree.
sl@0	3166	*/
sl@0	3167	static int exprWalkNoop(Walker pWalker, Expr pExpr){
sl@0	3168	return WRC_Continue;
sl@0	3169	}
sl@0	3170
sl@0	3171	/*
sl@0	3172	** This routine "expands" a SELECT statement and all of its subqueries.
sl@0	3173	** For additional information on what it means to "expand" a SELECT
sl@0	3174	** statement, see the comment on the selectExpand worker callback above.
sl@0	3175	**
sl@0	3176	** Expanding a SELECT statement is the first step in processing a
sl@0	3177	** SELECT statement. The SELECT statement must be expanded before
sl@0	3178	** name resolution is performed.
sl@0	3179	**
sl@0	3180	** If anything goes wrong, an error message is written into pParse.
sl@0	3181	** The calling function can detect the problem by looking at pParse->nErr
sl@0	3182	** and/or pParse->db->mallocFailed.
sl@0	3183	*/
sl@0	3184	static void sqlite3SelectExpand(Parse pParse, Select pSelect){
sl@0	3185	Walker w;
sl@0	3186	w.xSelectCallback = selectExpander;
sl@0	3187	w.xExprCallback = exprWalkNoop;
sl@0	3188	w.pParse = pParse;
sl@0	3189	sqlite3WalkSelect(&w, pSelect);
sl@0	3190	}
sl@0	3191
sl@0	3192
sl@0	3193	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	3194	/*
sl@0	3195	** This is a Walker.xSelectCallback callback for the sqlite3SelectTypeInfo()
sl@0	3196	** interface.
sl@0	3197	**
sl@0	3198	** For each FROM-clause subquery, add Column.zType and Column.zColl
sl@0	3199	** information to the Table structure that represents the result set
sl@0	3200	** of that subquery.
sl@0	3201	**
sl@0	3202	** The Table structure that represents the result set was constructed
sl@0	3203	** by selectExpander() but the type and collation information was omitted
sl@0	3204	** at that point because identifiers had not yet been resolved. This
sl@0	3205	** routine is called after identifier resolution.
sl@0	3206	*/
sl@0	3207	static int selectAddSubqueryTypeInfo(Walker pWalker, Select p){
sl@0	3208	Parse *pParse;
sl@0	3209	int i;
sl@0	3210	SrcList *pTabList;
sl@0	3211	struct SrcList_item *pFrom;
sl@0	3212
sl@0	3213	assert( p->selFlags & SF_Resolved );
sl@0	3214	if( (p->selFlags & SF_HasTypeInfo)==0 ){
sl@0	3215	p->selFlags \|= SF_HasTypeInfo;
sl@0	3216	pParse = pWalker->pParse;
sl@0	3217	pTabList = p->pSrc;
sl@0	3218	for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
sl@0	3219	Table *pTab = pFrom->pTab;
sl@0	3220	if( pTab && (pTab->tabFlags & TF_Ephemeral)!=0 ){
sl@0	3221	/* A sub-query in the FROM clause of a SELECT */
sl@0	3222	Select *pSel = pFrom->pSelect;
sl@0	3223	assert( pSel );
sl@0	3224	while( pSel->pPrior ) pSel = pSel->pPrior;
sl@0	3225	selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSel);
sl@0	3226	}
sl@0	3227	}
sl@0	3228	}
sl@0	3229	return WRC_Continue;
sl@0	3230	}
sl@0	3231	#endif
sl@0	3232
sl@0	3233
sl@0	3234	/*
sl@0	3235	** This routine adds datatype and collating sequence information to
sl@0	3236	** the Table structures of all FROM-clause subqueries in a
sl@0	3237	** SELECT statement.
sl@0	3238	**
sl@0	3239	** Use this routine after name resolution.
sl@0	3240	*/
sl@0	3241	static void sqlite3SelectAddTypeInfo(Parse pParse, Select pSelect){
sl@0	3242	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	3243	Walker w;
sl@0	3244	w.xSelectCallback = selectAddSubqueryTypeInfo;
sl@0	3245	w.xExprCallback = exprWalkNoop;
sl@0	3246	w.pParse = pParse;
sl@0	3247	sqlite3WalkSelect(&w, pSelect);
sl@0	3248	#endif
sl@0	3249	}
sl@0	3250
sl@0	3251
sl@0	3252	/*
sl@0	3253	** This routine sets of a SELECT statement for processing. The
sl@0	3254	** following is accomplished:
sl@0	3255	**
sl@0	3256	** * VDBE Cursor numbers are assigned to all FROM-clause terms.
sl@0	3257	** * Ephemeral Table objects are created for all FROM-clause subqueries.
sl@0	3258	** * ON and USING clauses are shifted into WHERE statements
sl@0	3259	** * Wildcards "" and "TABLE." in result sets are expanded.
sl@0	3260	** * Identifiers in expression are matched to tables.
sl@0	3261	**
sl@0	3262	** This routine acts recursively on all subqueries within the SELECT.
sl@0	3263	*/
sl@0	3264	void sqlite3SelectPrep(
sl@0	3265	Parse pParse, / The parser context */
sl@0	3266	Select p, / The SELECT statement being coded. */
sl@0	3267	NameContext pOuterNC / Name context for container */
sl@0	3268	){
sl@0	3269	sqlite3 *db;
sl@0	3270	if( p==0 ) return;
sl@0	3271	db = pParse->db;
sl@0	3272	if( p->selFlags & SF_HasTypeInfo ) return;
sl@0	3273	if( pParse->nErr \|\| db->mallocFailed ) return;
sl@0	3274	sqlite3SelectExpand(pParse, p);
sl@0	3275	if( pParse->nErr \|\| db->mallocFailed ) return;
sl@0	3276	sqlite3ResolveSelectNames(pParse, p, pOuterNC);
sl@0	3277	if( pParse->nErr \|\| db->mallocFailed ) return;
sl@0	3278	sqlite3SelectAddTypeInfo(pParse, p);
sl@0	3279	}
sl@0	3280
sl@0	3281	/*
sl@0	3282	** Reset the aggregate accumulator.
sl@0	3283	**
sl@0	3284	** The aggregate accumulator is a set of memory cells that hold
sl@0	3285	** intermediate results while calculating an aggregate. This
sl@0	3286	** routine simply stores NULLs in all of those memory cells.
sl@0	3287	*/
sl@0	3288	static void resetAccumulator(Parse pParse, AggInfo pAggInfo){
sl@0	3289	Vdbe *v = pParse->pVdbe;
sl@0	3290	int i;
sl@0	3291	struct AggInfo_func *pFunc;
sl@0	3292	if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
sl@0	3293	return;
sl@0	3294	}
sl@0	3295	for(i=0; i<pAggInfo->nColumn; i++){
sl@0	3296	sqlite3VdbeAddOp2(v, OP_Null, 0, pAggInfo->aCol[i].iMem);
sl@0	3297	}
sl@0	3298	for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
sl@0	3299	sqlite3VdbeAddOp2(v, OP_Null, 0, pFunc->iMem);
sl@0	3300	if( pFunc->iDistinct>=0 ){
sl@0	3301	Expr *pE = pFunc->pExpr;
sl@0	3302	if( pE->pList==0 \|\| pE->pList->nExpr!=1 ){
sl@0	3303	sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
sl@0	3304	"by an expression");
sl@0	3305	pFunc->iDistinct = -1;
sl@0	3306	}else{
sl@0	3307	KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
sl@0	3308	sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
sl@0	3309	(char*)pKeyInfo, P4_KEYINFO_HANDOFF);
sl@0	3310	}
sl@0	3311	}
sl@0	3312	}
sl@0	3313	}
sl@0	3314
sl@0	3315	/*
sl@0	3316	** Invoke the OP_AggFinalize opcode for every aggregate function
sl@0	3317	** in the AggInfo structure.
sl@0	3318	*/
sl@0	3319	static void finalizeAggFunctions(Parse pParse, AggInfo pAggInfo){
sl@0	3320	Vdbe *v = pParse->pVdbe;
sl@0	3321	int i;
sl@0	3322	struct AggInfo_func *pF;
sl@0	3323	for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
sl@0	3324	ExprList *pList = pF->pExpr->pList;
sl@0	3325	sqlite3VdbeAddOp4(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0, 0,
sl@0	3326	(void*)pF->pFunc, P4_FUNCDEF);
sl@0	3327	}
sl@0	3328	}
sl@0	3329
sl@0	3330	/*
sl@0	3331	** Update the accumulator memory cells for an aggregate based on
sl@0	3332	** the current cursor position.
sl@0	3333	*/
sl@0	3334	static void updateAccumulator(Parse pParse, AggInfo pAggInfo){
sl@0	3335	Vdbe *v = pParse->pVdbe;
sl@0	3336	int i;
sl@0	3337	struct AggInfo_func *pF;
sl@0	3338	struct AggInfo_col *pC;
sl@0	3339
sl@0	3340	pAggInfo->directMode = 1;
sl@0	3341	for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
sl@0	3342	int nArg;
sl@0	3343	int addrNext = 0;
sl@0	3344	int regAgg;
sl@0	3345	ExprList *pList = pF->pExpr->pList;
sl@0	3346	if( pList ){
sl@0	3347	nArg = pList->nExpr;
sl@0	3348	regAgg = sqlite3GetTempRange(pParse, nArg);
sl@0	3349	sqlite3ExprCodeExprList(pParse, pList, regAgg, 0);
sl@0	3350	}else{
sl@0	3351	nArg = 0;
sl@0	3352	regAgg = 0;
sl@0	3353	}
sl@0	3354	if( pF->iDistinct>=0 ){
sl@0	3355	addrNext = sqlite3VdbeMakeLabel(v);
sl@0	3356	assert( nArg==1 );
sl@0	3357	codeDistinct(pParse, pF->iDistinct, addrNext, 1, regAgg);
sl@0	3358	}
sl@0	3359	if( pF->pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
sl@0	3360	CollSeq *pColl = 0;
sl@0	3361	struct ExprList_item *pItem;
sl@0	3362	int j;
sl@0	3363	assert( pList!=0 ); /* pList!=0 if pF->pFunc has NEEDCOLL */
sl@0	3364	for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
sl@0	3365	pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
sl@0	3366	}
sl@0	3367	if( !pColl ){
sl@0	3368	pColl = pParse->db->pDfltColl;
sl@0	3369	}
sl@0	3370	sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
sl@0	3371	}
sl@0	3372	sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
sl@0	3373	(void*)pF->pFunc, P4_FUNCDEF);
sl@0	3374	sqlite3VdbeChangeP5(v, nArg);
sl@0	3375	sqlite3ReleaseTempRange(pParse, regAgg, nArg);
sl@0	3376	sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
sl@0	3377	if( addrNext ){
sl@0	3378	sqlite3VdbeResolveLabel(v, addrNext);
sl@0	3379	}
sl@0	3380	}
sl@0	3381	for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
sl@0	3382	sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
sl@0	3383	}
sl@0	3384	pAggInfo->directMode = 0;
sl@0	3385	}
sl@0	3386
sl@0	3387	/*
sl@0	3388	** Generate code for the SELECT statement given in the p argument.
sl@0	3389	**
sl@0	3390	** The results are distributed in various ways depending on the
sl@0	3391	** contents of the SelectDest structure pointed to by argument pDest
sl@0	3392	** as follows:
sl@0	3393	**
sl@0	3394	** pDest->eDest Result
sl@0	3395	** ------------ -------------------------------------------
sl@0	3396	** SRT_Output Generate a row of output (using the OP_ResultRow
sl@0	3397	** opcode) for each row in the result set.
sl@0	3398	**
sl@0	3399	** SRT_Mem Only valid if the result is a single column.
sl@0	3400	** Store the first column of the first result row
sl@0	3401	** in register pDest->iParm then abandon the rest
sl@0	3402	** of the query. This destination implies "LIMIT 1".
sl@0	3403	**
sl@0	3404	** SRT_Set The result must be a single column. Store each
sl@0	3405	** row of result as the key in table pDest->iParm.
sl@0	3406	** Apply the affinity pDest->affinity before storing
sl@0	3407	** results. Used to implement "IN (SELECT ...)".
sl@0	3408	**
sl@0	3409	** SRT_Union Store results as a key in a temporary table pDest->iParm.
sl@0	3410	**
sl@0	3411	** SRT_Except Remove results from the temporary table pDest->iParm.
sl@0	3412	**
sl@0	3413	** SRT_Table Store results in temporary table pDest->iParm.
sl@0	3414	** This is like SRT_EphemTab except that the table
sl@0	3415	** is assumed to already be open.
sl@0	3416	**
sl@0	3417	** SRT_EphemTab Create an temporary table pDest->iParm and store
sl@0	3418	** the result there. The cursor is left open after
sl@0	3419	** returning. This is like SRT_Table except that
sl@0	3420	** this destination uses OP_OpenEphemeral to create
sl@0	3421	** the table first.
sl@0	3422	**
sl@0	3423	** SRT_Coroutine Generate a co-routine that returns a new row of
sl@0	3424	** results each time it is invoked. The entry point
sl@0	3425	** of the co-routine is stored in register pDest->iParm.
sl@0	3426	**
sl@0	3427	** SRT_Exists Store a 1 in memory cell pDest->iParm if the result
sl@0	3428	** set is not empty.
sl@0	3429	**
sl@0	3430	** SRT_Discard Throw the results away. This is used by SELECT
sl@0	3431	** statements within triggers whose only purpose is
sl@0	3432	** the side-effects of functions.
sl@0	3433	**
sl@0	3434	** This routine returns the number of errors. If any errors are
sl@0	3435	** encountered, then an appropriate error message is left in
sl@0	3436	** pParse->zErrMsg.
sl@0	3437	**
sl@0	3438	** This routine does NOT free the Select structure passed in. The
sl@0	3439	** calling function needs to do that.
sl@0	3440	*/
sl@0	3441	int sqlite3Select(
sl@0	3442	Parse pParse, / The parser context */
sl@0	3443	Select p, / The SELECT statement being coded. */
sl@0	3444	SelectDest pDest / What to do with the query results */
sl@0	3445	){
sl@0	3446	int i, j; /* Loop counters */
sl@0	3447	WhereInfo pWInfo; / Return from sqlite3WhereBegin() */
sl@0	3448	Vdbe v; / The virtual machine under construction */
sl@0	3449	int isAgg; /* True for select lists like "count()" /
sl@0	3450	ExprList pEList; / List of columns to extract. */
sl@0	3451	SrcList pTabList; / List of tables to select from */
sl@0	3452	Expr pWhere; / The WHERE clause. May be NULL */
sl@0	3453	ExprList pOrderBy; / The ORDER BY clause. May be NULL */
sl@0	3454	ExprList pGroupBy; / The GROUP BY clause. May be NULL */
sl@0	3455	Expr pHaving; / The HAVING clause. May be NULL */
sl@0	3456	int isDistinct; /* True if the DISTINCT keyword is present */
sl@0	3457	int distinct; /* Table to use for the distinct set */
sl@0	3458	int rc = 1; /* Value to return from this function */
sl@0	3459	int addrSortIndex; /* Address of an OP_OpenEphemeral instruction */
sl@0	3460	AggInfo sAggInfo; /* Information used by aggregate queries */
sl@0	3461	int iEnd; /* Address of the end of the query */
sl@0	3462	sqlite3 db; / The database connection */
sl@0	3463
sl@0	3464	db = pParse->db;
sl@0	3465	if( p==0 \|\| db->mallocFailed \|\| pParse->nErr ){
sl@0	3466	return 1;
sl@0	3467	}
sl@0	3468	if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
sl@0	3469	memset(&sAggInfo, 0, sizeof(sAggInfo));
sl@0	3470
sl@0	3471	pOrderBy = p->pOrderBy;
sl@0	3472	if( IgnorableOrderby(pDest) ){
sl@0	3473	p->pOrderBy = 0;
sl@0	3474
sl@0	3475	/* In these cases the DISTINCT operator makes no difference to the
sl@0	3476	** results, so remove it if it were specified.
sl@0	3477	*/
sl@0	3478	assert(pDest->eDest==SRT_Exists \|\| pDest->eDest==SRT_Union \|\|
sl@0	3479	pDest->eDest==SRT_Except \|\| pDest->eDest==SRT_Discard);
sl@0	3480	p->selFlags &= ~SF_Distinct;
sl@0	3481	}
sl@0	3482	sqlite3SelectPrep(pParse, p, 0);
sl@0	3483	if( pParse->nErr ){
sl@0	3484	goto select_end;
sl@0	3485	}
sl@0	3486	p->pOrderBy = pOrderBy;
sl@0	3487
sl@0	3488
sl@0	3489	/* Make local copies of the parameters for this query.
sl@0	3490	*/
sl@0	3491	pTabList = p->pSrc;
sl@0	3492	isAgg = (p->selFlags & SF_Aggregate)!=0;
sl@0	3493	pEList = p->pEList;
sl@0	3494	if( pEList==0 ) goto select_end;
sl@0	3495
sl@0	3496	/*
sl@0	3497	** Do not even attempt to generate any code if we have already seen
sl@0	3498	** errors before this routine starts.
sl@0	3499	*/
sl@0	3500	if( pParse->nErr>0 ) goto select_end;
sl@0	3501
sl@0	3502	/* ORDER BY is ignored for some destinations.
sl@0	3503	*/
sl@0	3504	if( IgnorableOrderby(pDest) ){
sl@0	3505	pOrderBy = 0;
sl@0	3506	}
sl@0	3507
sl@0	3508	/* Begin generating code.
sl@0	3509	*/
sl@0	3510	v = sqlite3GetVdbe(pParse);
sl@0	3511	if( v==0 ) goto select_end;
sl@0	3512
sl@0	3513	/* Generate code for all sub-queries in the FROM clause
sl@0	3514	*/
sl@0	3515	#if !defined(SQLITE_OMIT_SUBQUERY) \|\| !defined(SQLITE_OMIT_VIEW)
sl@0	3516	for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
sl@0	3517	struct SrcList_item *pItem = &pTabList->a[i];
sl@0	3518	SelectDest dest;
sl@0	3519	Select *pSub = pItem->pSelect;
sl@0	3520	int isAggSub;
sl@0	3521
sl@0	3522	if( pSub==0 \|\| pItem->isPopulated ) continue;
sl@0	3523
sl@0	3524	/* Increment Parse.nHeight by the height of the largest expression
sl@0	3525	** tree refered to by this, the parent select. The child select
sl@0	3526	** may contain expression trees of at most
sl@0	3527	** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
sl@0	3528	** more conservative than necessary, but much easier than enforcing
sl@0	3529	** an exact limit.
sl@0	3530	*/
sl@0	3531	pParse->nHeight += sqlite3SelectExprHeight(p);
sl@0	3532
sl@0	3533	/* Check to see if the subquery can be absorbed into the parent. */
sl@0	3534	isAggSub = (pSub->selFlags & SF_Aggregate)!=0;
sl@0	3535	if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
sl@0	3536	if( isAggSub ){
sl@0	3537	isAgg = 1;
sl@0	3538	p->selFlags \|= SF_Aggregate;
sl@0	3539	}
sl@0	3540	i = -1;
sl@0	3541	}else{
sl@0	3542	sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
sl@0	3543	assert( pItem->isPopulated==0 );
sl@0	3544	sqlite3Select(pParse, pSub, &dest);
sl@0	3545	pItem->isPopulated = 1;
sl@0	3546	}
sl@0	3547	if( pParse->nErr \|\| db->mallocFailed ){
sl@0	3548	goto select_end;
sl@0	3549	}
sl@0	3550	pParse->nHeight -= sqlite3SelectExprHeight(p);
sl@0	3551	pTabList = p->pSrc;
sl@0	3552	if( !IgnorableOrderby(pDest) ){
sl@0	3553	pOrderBy = p->pOrderBy;
sl@0	3554	}
sl@0	3555	}
sl@0	3556	pEList = p->pEList;
sl@0	3557	#endif
sl@0	3558	pWhere = p->pWhere;
sl@0	3559	pGroupBy = p->pGroupBy;
sl@0	3560	pHaving = p->pHaving;
sl@0	3561	isDistinct = (p->selFlags & SF_Distinct)!=0;
sl@0	3562
sl@0	3563	#ifndef SQLITE_OMIT_COMPOUND_SELECT
sl@0	3564	/* If there is are a sequence of queries, do the earlier ones first.
sl@0	3565	*/
sl@0	3566	if( p->pPrior ){
sl@0	3567	if( p->pRightmost==0 ){
sl@0	3568	Select pLoop, pRight = 0;
sl@0	3569	int cnt = 0;
sl@0	3570	int mxSelect;
sl@0	3571	for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
sl@0	3572	pLoop->pRightmost = p;
sl@0	3573	pLoop->pNext = pRight;
sl@0	3574	pRight = pLoop;
sl@0	3575	}
sl@0	3576	mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
sl@0	3577	if( mxSelect && cnt>mxSelect ){
sl@0	3578	sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
sl@0	3579	return 1;
sl@0	3580	}
sl@0	3581	}
sl@0	3582	return multiSelect(pParse, p, pDest);
sl@0	3583	}
sl@0	3584	#endif
sl@0	3585
sl@0	3586	/* If writing to memory or generating a set
sl@0	3587	** only a single column may be output.
sl@0	3588	*/
sl@0	3589	#ifndef SQLITE_OMIT_SUBQUERY
sl@0	3590	if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
sl@0	3591	goto select_end;
sl@0	3592	}
sl@0	3593	#endif
sl@0	3594
sl@0	3595	/* If possible, rewrite the query to use GROUP BY instead of DISTINCT.
sl@0	3596	** GROUP BY might use an index, DISTINCT never does.
sl@0	3597	*/
sl@0	3598	if( (p->selFlags & (SF_Distinct\|SF_Aggregate))==SF_Distinct && !p->pGroupBy ){
sl@0	3599	p->pGroupBy = sqlite3ExprListDup(db, p->pEList);
sl@0	3600	pGroupBy = p->pGroupBy;
sl@0	3601	p->selFlags &= ~SF_Distinct;
sl@0	3602	isDistinct = 0;
sl@0	3603	}
sl@0	3604
sl@0	3605	/* If there is an ORDER BY clause, then this sorting
sl@0	3606	** index might end up being unused if the data can be
sl@0	3607	** extracted in pre-sorted order. If that is the case, then the
sl@0	3608	** OP_OpenEphemeral instruction will be changed to an OP_Noop once
sl@0	3609	** we figure out that the sorting index is not needed. The addrSortIndex
sl@0	3610	** variable is used to facilitate that change.
sl@0	3611	*/
sl@0	3612	if( pOrderBy ){
sl@0	3613	KeyInfo *pKeyInfo;
sl@0	3614	pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
sl@0	3615	pOrderBy->iECursor = pParse->nTab++;
sl@0	3616	p->addrOpenEphm[2] = addrSortIndex =
sl@0	3617	sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
sl@0	3618	pOrderBy->iECursor, pOrderBy->nExpr+2, 0,
sl@0	3619	(char*)pKeyInfo, P4_KEYINFO_HANDOFF);
sl@0	3620	}else{
sl@0	3621	addrSortIndex = -1;
sl@0	3622	}
sl@0	3623
sl@0	3624	/* If the output is destined for a temporary table, open that table.
sl@0	3625	*/
sl@0	3626	if( pDest->eDest==SRT_EphemTab ){
sl@0	3627	sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iParm, pEList->nExpr);
sl@0	3628	}
sl@0	3629
sl@0	3630	/* Set the limiter.
sl@0	3631	*/
sl@0	3632	iEnd = sqlite3VdbeMakeLabel(v);
sl@0	3633	computeLimitRegisters(pParse, p, iEnd);
sl@0	3634
sl@0	3635	/* Open a virtual index to use for the distinct set.
sl@0	3636	*/
sl@0	3637	if( isDistinct ){
sl@0	3638	KeyInfo *pKeyInfo;
sl@0	3639	assert( isAgg \|\| pGroupBy );
sl@0	3640	distinct = pParse->nTab++;
sl@0	3641	pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
sl@0	3642	sqlite3VdbeAddOp4(v, OP_OpenEphemeral, distinct, 0, 0,
sl@0	3643	(char*)pKeyInfo, P4_KEYINFO_HANDOFF);
sl@0	3644	}else{
sl@0	3645	distinct = -1;
sl@0	3646	}
sl@0	3647
sl@0	3648	/* Aggregate and non-aggregate queries are handled differently */
sl@0	3649	if( !isAgg && pGroupBy==0 ){
sl@0	3650	/* This case is for non-aggregate queries
sl@0	3651	** Begin the database scan
sl@0	3652	*/
sl@0	3653	pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, 0);
sl@0	3654	if( pWInfo==0 ) goto select_end;
sl@0	3655
sl@0	3656	/* If sorting index that was created by a prior OP_OpenEphemeral
sl@0	3657	** instruction ended up not being needed, then change the OP_OpenEphemeral
sl@0	3658	** into an OP_Noop.
sl@0	3659	*/
sl@0	3660	if( addrSortIndex>=0 && pOrderBy==0 ){
sl@0	3661	sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
sl@0	3662	p->addrOpenEphm[2] = -1;
sl@0	3663	}
sl@0	3664
sl@0	3665	/* Use the standard inner loop
sl@0	3666	*/
sl@0	3667	assert(!isDistinct);
sl@0	3668	selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, pDest,
sl@0	3669	pWInfo->iContinue, pWInfo->iBreak);
sl@0	3670
sl@0	3671	/* End the database scan loop.
sl@0	3672	*/
sl@0	3673	sqlite3WhereEnd(pWInfo);
sl@0	3674	}else{
sl@0	3675	/* This is the processing for aggregate queries */
sl@0	3676	NameContext sNC; /* Name context for processing aggregate information */
sl@0	3677	int iAMem; /* First Mem address for storing current GROUP BY */
sl@0	3678	int iBMem; /* First Mem address for previous GROUP BY */
sl@0	3679	int iUseFlag; /* Mem address holding flag indicating that at least
sl@0	3680	** one row of the input to the aggregator has been
sl@0	3681	** processed */
sl@0	3682	int iAbortFlag; /* Mem address which causes query abort if positive */
sl@0	3683	int groupBySort; /* Rows come from source in GROUP BY order */
sl@0	3684	int addrEnd; /* End of processing for this SELECT */
sl@0	3685
sl@0	3686	/* Remove any and all aliases between the result set and the
sl@0	3687	** GROUP BY clause.
sl@0	3688	*/
sl@0	3689	if( pGroupBy ){
sl@0	3690	int i; /* Loop counter */
sl@0	3691	struct ExprList_item pItem; / For looping over expression in a list */
sl@0	3692
sl@0	3693	for(i=p->pEList->nExpr, pItem=p->pEList->a; i>0; i--, pItem++){
sl@0	3694	pItem->iAlias = 0;
sl@0	3695	}
sl@0	3696	for(i=pGroupBy->nExpr, pItem=pGroupBy->a; i>0; i--, pItem++){
sl@0	3697	pItem->iAlias = 0;
sl@0	3698	}
sl@0	3699	}
sl@0	3700
sl@0	3701
sl@0	3702	/* Create a label to jump to when we want to abort the query */
sl@0	3703	addrEnd = sqlite3VdbeMakeLabel(v);
sl@0	3704
sl@0	3705	/* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
sl@0	3706	** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
sl@0	3707	** SELECT statement.
sl@0	3708	*/
sl@0	3709	memset(&sNC, 0, sizeof(sNC));
sl@0	3710	sNC.pParse = pParse;
sl@0	3711	sNC.pSrcList = pTabList;
sl@0	3712	sNC.pAggInfo = &sAggInfo;
sl@0	3713	sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
sl@0	3714	sAggInfo.pGroupBy = pGroupBy;
sl@0	3715	sqlite3ExprAnalyzeAggList(&sNC, pEList);
sl@0	3716	sqlite3ExprAnalyzeAggList(&sNC, pOrderBy);
sl@0	3717	if( pHaving ){
sl@0	3718	sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
sl@0	3719	}
sl@0	3720	sAggInfo.nAccumulator = sAggInfo.nColumn;
sl@0	3721	for(i=0; i<sAggInfo.nFunc; i++){
sl@0	3722	sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList);
sl@0	3723	}
sl@0	3724	if( db->mallocFailed ) goto select_end;
sl@0	3725
sl@0	3726	/* Processing for aggregates with GROUP BY is very different and
sl@0	3727	** much more complex than aggregates without a GROUP BY.
sl@0	3728	*/
sl@0	3729	if( pGroupBy ){
sl@0	3730	KeyInfo pKeyInfo; / Keying information for the group by clause */
sl@0	3731	int j1; /* A-vs-B comparision jump */
sl@0	3732	int addrOutputRow; /* Start of subroutine that outputs a result row */
sl@0	3733	int regOutputRow; /* Return address register for output subroutine */
sl@0	3734	int addrSetAbort; /* Set the abort flag and return */
sl@0	3735	int addrTopOfLoop; /* Top of the input loop */
sl@0	3736	int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
sl@0	3737	int addrReset; /* Subroutine for resetting the accumulator */
sl@0	3738	int regReset; /* Return address register for reset subroutine */
sl@0	3739
sl@0	3740	/* If there is a GROUP BY clause we might need a sorting index to
sl@0	3741	** implement it. Allocate that sorting index now. If it turns out
sl@0	3742	** that we do not need it after all, the OpenEphemeral instruction
sl@0	3743	** will be converted into a Noop.
sl@0	3744	*/
sl@0	3745	sAggInfo.sortingIdx = pParse->nTab++;
sl@0	3746	pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
sl@0	3747	addrSortingIdx = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
sl@0	3748	sAggInfo.sortingIdx, sAggInfo.nSortingColumn,
sl@0	3749	0, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
sl@0	3750
sl@0	3751	/* Initialize memory locations used by GROUP BY aggregate processing
sl@0	3752	*/
sl@0	3753	iUseFlag = ++pParse->nMem;
sl@0	3754	iAbortFlag = ++pParse->nMem;
sl@0	3755	regOutputRow = ++pParse->nMem;
sl@0	3756	addrOutputRow = sqlite3VdbeMakeLabel(v);
sl@0	3757	regReset = ++pParse->nMem;
sl@0	3758	addrReset = sqlite3VdbeMakeLabel(v);
sl@0	3759	iAMem = pParse->nMem + 1;
sl@0	3760	pParse->nMem += pGroupBy->nExpr;
sl@0	3761	iBMem = pParse->nMem + 1;
sl@0	3762	pParse->nMem += pGroupBy->nExpr;
sl@0	3763	sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
sl@0	3764	VdbeComment((v, "clear abort flag"));
sl@0	3765	sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
sl@0	3766	VdbeComment((v, "indicate accumulator empty"));
sl@0	3767
sl@0	3768	/* Begin a loop that will extract all source rows in GROUP BY order.
sl@0	3769	** This might involve two separate loops with an OP_Sort in between, or
sl@0	3770	** it might be a single loop that uses an index to extract information
sl@0	3771	** in the right order to begin with.
sl@0	3772	*/
sl@0	3773	sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
sl@0	3774	pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0);
sl@0	3775	if( pWInfo==0 ) goto select_end;
sl@0	3776	if( pGroupBy==0 ){
sl@0	3777	/* The optimizer is able to deliver rows in group by order so
sl@0	3778	** we do not have to sort. The OP_OpenEphemeral table will be
sl@0	3779	** cancelled later because we still need to use the pKeyInfo
sl@0	3780	*/
sl@0	3781	pGroupBy = p->pGroupBy;
sl@0	3782	groupBySort = 0;
sl@0	3783	}else{
sl@0	3784	/* Rows are coming out in undetermined order. We have to push
sl@0	3785	** each row into a sorting index, terminate the first loop,
sl@0	3786	** then loop over the sorting index in order to get the output
sl@0	3787	** in sorted order
sl@0	3788	*/
sl@0	3789	int regBase;
sl@0	3790	int regRecord;
sl@0	3791	int nCol;
sl@0	3792	int nGroupBy;
sl@0	3793
sl@0	3794	groupBySort = 1;
sl@0	3795	nGroupBy = pGroupBy->nExpr;
sl@0	3796	nCol = nGroupBy + 1;
sl@0	3797	j = nGroupBy+1;
sl@0	3798	for(i=0; i<sAggInfo.nColumn; i++){
sl@0	3799	if( sAggInfo.aCol[i].iSorterColumn>=j ){
sl@0	3800	nCol++;
sl@0	3801	j++;
sl@0	3802	}
sl@0	3803	}
sl@0	3804	regBase = sqlite3GetTempRange(pParse, nCol);
sl@0	3805	sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0);
sl@0	3806	sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx,regBase+nGroupBy);
sl@0	3807	j = nGroupBy+1;
sl@0	3808	for(i=0; i<sAggInfo.nColumn; i++){
sl@0	3809	struct AggInfo_col *pCol = &sAggInfo.aCol[i];
sl@0	3810	if( pCol->iSorterColumn>=j ){
sl@0	3811	int r1 = j + regBase;
sl@0	3812	int r2;
sl@0	3813
sl@0	3814	r2 = sqlite3ExprCodeGetColumn(pParse,
sl@0	3815	pCol->pTab, pCol->iColumn, pCol->iTable, r1, 0);
sl@0	3816	if( r1!=r2 ){
sl@0	3817	sqlite3VdbeAddOp2(v, OP_SCopy, r2, r1);
sl@0	3818	}
sl@0	3819	j++;
sl@0	3820	}
sl@0	3821	}
sl@0	3822	regRecord = sqlite3GetTempReg(pParse);
sl@0	3823	sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
sl@0	3824	sqlite3VdbeAddOp2(v, OP_IdxInsert, sAggInfo.sortingIdx, regRecord);
sl@0	3825	sqlite3ReleaseTempReg(pParse, regRecord);
sl@0	3826	sqlite3ReleaseTempRange(pParse, regBase, nCol);
sl@0	3827	sqlite3WhereEnd(pWInfo);
sl@0	3828	sqlite3VdbeAddOp2(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
sl@0	3829	VdbeComment((v, "GROUP BY sort"));
sl@0	3830	sAggInfo.useSortingIdx = 1;
sl@0	3831	}
sl@0	3832
sl@0	3833	/* Evaluate the current GROUP BY terms and store in b0, b1, b2...
sl@0	3834	** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
sl@0	3835	** Then compare the current GROUP BY terms against the GROUP BY terms
sl@0	3836	** from the previous row currently stored in a0, a1, a2...
sl@0	3837	*/
sl@0	3838	addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
sl@0	3839	for(j=0; j<pGroupBy->nExpr; j++){
sl@0	3840	if( groupBySort ){
sl@0	3841	sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
sl@0	3842	}else{
sl@0	3843	sAggInfo.directMode = 1;
sl@0	3844	sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
sl@0	3845	}
sl@0	3846	}
sl@0	3847	sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
sl@0	3848	(char*)pKeyInfo, P4_KEYINFO);
sl@0	3849	j1 = sqlite3VdbeCurrentAddr(v);
sl@0	3850	sqlite3VdbeAddOp3(v, OP_Jump, j1+1, 0, j1+1);
sl@0	3851
sl@0	3852	/* Generate code that runs whenever the GROUP BY changes.
sl@0	3853	** Changes in the GROUP BY are detected by the previous code
sl@0	3854	** block. If there were no changes, this block is skipped.
sl@0	3855	**
sl@0	3856	** This code copies current group by terms in b0,b1,b2,...
sl@0	3857	** over to a0,a1,a2. It then calls the output subroutine
sl@0	3858	** and resets the aggregate accumulator registers in preparation
sl@0	3859	** for the next GROUP BY batch.
sl@0	3860	*/
sl@0	3861	sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr);
sl@0	3862	sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
sl@0	3863	VdbeComment((v, "output one row"));
sl@0	3864	sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd);
sl@0	3865	VdbeComment((v, "check abort flag"));
sl@0	3866	sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
sl@0	3867	VdbeComment((v, "reset accumulator"));
sl@0	3868
sl@0	3869	/* Update the aggregate accumulators based on the content of
sl@0	3870	** the current row
sl@0	3871	*/
sl@0	3872	sqlite3VdbeJumpHere(v, j1);
sl@0	3873	updateAccumulator(pParse, &sAggInfo);
sl@0	3874	sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
sl@0	3875	VdbeComment((v, "indicate data in accumulator"));
sl@0	3876
sl@0	3877	/* End of the loop
sl@0	3878	*/
sl@0	3879	if( groupBySort ){
sl@0	3880	sqlite3VdbeAddOp2(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
sl@0	3881	}else{
sl@0	3882	sqlite3WhereEnd(pWInfo);
sl@0	3883	sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
sl@0	3884	}
sl@0	3885
sl@0	3886	/* Output the final row of result
sl@0	3887	*/
sl@0	3888	sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
sl@0	3889	VdbeComment((v, "output final row"));
sl@0	3890
sl@0	3891	/* Jump over the subroutines
sl@0	3892	*/
sl@0	3893	sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEnd);
sl@0	3894
sl@0	3895	/* Generate a subroutine that outputs a single row of the result
sl@0	3896	** set. This subroutine first looks at the iUseFlag. If iUseFlag
sl@0	3897	** is less than or equal to zero, the subroutine is a no-op. If
sl@0	3898	** the processing calls for the query to abort, this subroutine
sl@0	3899	** increments the iAbortFlag memory location before returning in
sl@0	3900	** order to signal the caller to abort.
sl@0	3901	*/
sl@0	3902	addrSetAbort = sqlite3VdbeCurrentAddr(v);
sl@0	3903	sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag);
sl@0	3904	VdbeComment((v, "set abort flag"));
sl@0	3905	sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
sl@0	3906	sqlite3VdbeResolveLabel(v, addrOutputRow);
sl@0	3907	addrOutputRow = sqlite3VdbeCurrentAddr(v);
sl@0	3908	sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2);
sl@0	3909	VdbeComment((v, "Groupby result generator entry point"));
sl@0	3910	sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
sl@0	3911	finalizeAggFunctions(pParse, &sAggInfo);
sl@0	3912	if( pHaving ){
sl@0	3913	sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
sl@0	3914	}
sl@0	3915	selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
sl@0	3916	distinct, pDest,
sl@0	3917	addrOutputRow+1, addrSetAbort);
sl@0	3918	sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
sl@0	3919	VdbeComment((v, "end groupby result generator"));
sl@0	3920
sl@0	3921	/* Generate a subroutine that will reset the group-by accumulator
sl@0	3922	*/
sl@0	3923	sqlite3VdbeResolveLabel(v, addrReset);
sl@0	3924	resetAccumulator(pParse, &sAggInfo);
sl@0	3925	sqlite3VdbeAddOp1(v, OP_Return, regReset);
sl@0	3926
sl@0	3927	} /* endif pGroupBy */
sl@0	3928	else {
sl@0	3929	ExprList *pMinMax = 0;
sl@0	3930	ExprList *pDel = 0;
sl@0	3931	u8 flag;
sl@0	3932
sl@0	3933	/* Check if the query is of one of the following forms:
sl@0	3934	**
sl@0	3935	** SELECT min(x) FROM ...
sl@0	3936	** SELECT max(x) FROM ...
sl@0	3937	**
sl@0	3938	** If it is, then ask the code in where.c to attempt to sort results
sl@0	3939	** as if there was an "ORDER ON x" or "ORDER ON x DESC" clause.
sl@0	3940	** If where.c is able to produce results sorted in this order, then
sl@0	3941	** add vdbe code to break out of the processing loop after the
sl@0	3942	** first iteration (since the first iteration of the loop is
sl@0	3943	** guaranteed to operate on the row with the minimum or maximum
sl@0	3944	** value of x, the only row required).
sl@0	3945	**
sl@0	3946	** A special flag must be passed to sqlite3WhereBegin() to slightly
sl@0	3947	** modify behaviour as follows:
sl@0	3948	**
sl@0	3949	** + If the query is a "SELECT min(x)", then the loop coded by
sl@0	3950	** where.c should not iterate over any values with a NULL value
sl@0	3951	** for x.
sl@0	3952	**
sl@0	3953	** + The optimizer code in where.c (the thing that decides which
sl@0	3954	** index or indices to use) should place a different priority on
sl@0	3955	** satisfying the 'ORDER BY' clause than it does in other cases.
sl@0	3956	** Refer to code and comments in where.c for details.
sl@0	3957	*/
sl@0	3958	flag = minMaxQuery(pParse, p);
sl@0	3959	if( flag ){
sl@0	3960	pDel = pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->pList);
sl@0	3961	if( pMinMax && !db->mallocFailed ){
sl@0	3962	pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN;
sl@0	3963	pMinMax->a[0].pExpr->op = TK_COLUMN;
sl@0	3964	}
sl@0	3965	}
sl@0	3966
sl@0	3967	/* This case runs if the aggregate has no GROUP BY clause. The
sl@0	3968	** processing is much simpler since there is only a single row
sl@0	3969	** of output.
sl@0	3970	*/
sl@0	3971	resetAccumulator(pParse, &sAggInfo);
sl@0	3972	pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax, flag);
sl@0	3973	if( pWInfo==0 ){
sl@0	3974	sqlite3ExprListDelete(db, pDel);
sl@0	3975	goto select_end;
sl@0	3976	}
sl@0	3977	updateAccumulator(pParse, &sAggInfo);
sl@0	3978	if( !pMinMax && flag ){
sl@0	3979	sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
sl@0	3980	VdbeComment((v, "%s() by index",(flag==WHERE_ORDERBY_MIN?"min":"max")));
sl@0	3981	}
sl@0	3982	sqlite3WhereEnd(pWInfo);
sl@0	3983	finalizeAggFunctions(pParse, &sAggInfo);
sl@0	3984	pOrderBy = 0;
sl@0	3985	if( pHaving ){
sl@0	3986	sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
sl@0	3987	}
sl@0	3988	selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1,
sl@0	3989	pDest, addrEnd, addrEnd);
sl@0	3990
sl@0	3991	sqlite3ExprListDelete(db, pDel);
sl@0	3992	}
sl@0	3993	sqlite3VdbeResolveLabel(v, addrEnd);
sl@0	3994
sl@0	3995	} /* endif aggregate query */
sl@0	3996
sl@0	3997	/* If there is an ORDER BY clause, then we need to sort the results
sl@0	3998	** and send them to the callback one by one.
sl@0	3999	*/
sl@0	4000	if( pOrderBy ){
sl@0	4001	generateSortTail(pParse, p, v, pEList->nExpr, pDest);
sl@0	4002	}
sl@0	4003
sl@0	4004	/* Jump here to skip this query
sl@0	4005	*/
sl@0	4006	sqlite3VdbeResolveLabel(v, iEnd);
sl@0	4007
sl@0	4008	/* The SELECT was successfully coded. Set the return code to 0
sl@0	4009	** to indicate no errors.
sl@0	4010	*/
sl@0	4011	rc = 0;
sl@0	4012
sl@0	4013	/* Control jumps to here if an error is encountered above, or upon
sl@0	4014	** successful coding of the SELECT.
sl@0	4015	*/
sl@0	4016	select_end:
sl@0	4017
sl@0	4018	/* Identify column names if results of the SELECT are to be output.
sl@0	4019	*/
sl@0	4020	if( rc==SQLITE_OK && pDest->eDest==SRT_Output ){
sl@0	4021	generateColumnNames(pParse, pTabList, pEList);
sl@0	4022	}
sl@0	4023
sl@0	4024	sqlite3DbFree(db, sAggInfo.aCol);
sl@0	4025	sqlite3DbFree(db, sAggInfo.aFunc);
sl@0	4026	return rc;
sl@0	4027	}
sl@0	4028
sl@0	4029	#if defined(SQLITE_DEBUG)
sl@0	4030	/*
sl@0	4031	*******************************************************************************
sl@0	4032	** The following code is used for testing and debugging only. The code
sl@0	4033	** that follows does not appear in normal builds.
sl@0	4034	**
sl@0	4035	** These routines are used to print out the content of all or part of a
sl@0	4036	** parse structures such as Select or Expr. Such printouts are useful
sl@0	4037	** for helping to understand what is happening inside the code generator
sl@0	4038	** during the execution of complex SELECT statements.
sl@0	4039	**
sl@0	4040	** These routine are not called anywhere from within the normal
sl@0	4041	** code base. Then are intended to be called from within the debugger
sl@0	4042	** or from temporary "printf" statements inserted for debugging.
sl@0	4043	*/
sl@0	4044	void sqlite3PrintExpr(Expr *p){
sl@0	4045	if( p->token.z && p->token.n>0 ){
sl@0	4046	sqlite3DebugPrintf("(%.*s", p->token.n, p->token.z);
sl@0	4047	}else{
sl@0	4048	sqlite3DebugPrintf("(%d", p->op);
sl@0	4049	}
sl@0	4050	if( p->pLeft ){
sl@0	4051	sqlite3DebugPrintf(" ");
sl@0	4052	sqlite3PrintExpr(p->pLeft);
sl@0	4053	}
sl@0	4054	if( p->pRight ){
sl@0	4055	sqlite3DebugPrintf(" ");
sl@0	4056	sqlite3PrintExpr(p->pRight);
sl@0	4057	}
sl@0	4058	sqlite3DebugPrintf(")");
sl@0	4059	}
sl@0	4060	void sqlite3PrintExprList(ExprList *pList){
sl@0	4061	int i;
sl@0	4062	for(i=0; i<pList->nExpr; i++){
sl@0	4063	sqlite3PrintExpr(pList->a[i].pExpr);
sl@0	4064	if( i<pList->nExpr-1 ){
sl@0	4065	sqlite3DebugPrintf(", ");
sl@0	4066	}
sl@0	4067	}
sl@0	4068	}
sl@0	4069	void sqlite3PrintSelect(Select *p, int indent){
sl@0	4070	sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
sl@0	4071	sqlite3PrintExprList(p->pEList);
sl@0	4072	sqlite3DebugPrintf("\n");
sl@0	4073	if( p->pSrc ){
sl@0	4074	char *zPrefix;
sl@0	4075	int i;
sl@0	4076	zPrefix = "FROM";
sl@0	4077	for(i=0; i<p->pSrc->nSrc; i++){
sl@0	4078	struct SrcList_item *pItem = &p->pSrc->a[i];
sl@0	4079	sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
sl@0	4080	zPrefix = "";
sl@0	4081	if( pItem->pSelect ){
sl@0	4082	sqlite3DebugPrintf("(\n");
sl@0	4083	sqlite3PrintSelect(pItem->pSelect, indent+10);
sl@0	4084	sqlite3DebugPrintf("%*s)", indent+8, "");
sl@0	4085	}else if( pItem->zName ){
sl@0	4086	sqlite3DebugPrintf("%s", pItem->zName);
sl@0	4087	}
sl@0	4088	if( pItem->pTab ){
sl@0	4089	sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
sl@0	4090	}
sl@0	4091	if( pItem->zAlias ){
sl@0	4092	sqlite3DebugPrintf(" AS %s", pItem->zAlias);
sl@0	4093	}
sl@0	4094	if( i<p->pSrc->nSrc-1 ){
sl@0	4095	sqlite3DebugPrintf(",");
sl@0	4096	}
sl@0	4097	sqlite3DebugPrintf("\n");
sl@0	4098	}
sl@0	4099	}
sl@0	4100	if( p->pWhere ){
sl@0	4101	sqlite3DebugPrintf("%*s WHERE ", indent, "");
sl@0	4102	sqlite3PrintExpr(p->pWhere);
sl@0	4103	sqlite3DebugPrintf("\n");
sl@0	4104	}
sl@0	4105	if( p->pGroupBy ){
sl@0	4106	sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
sl@0	4107	sqlite3PrintExprList(p->pGroupBy);
sl@0	4108	sqlite3DebugPrintf("\n");
sl@0	4109	}
sl@0	4110	if( p->pHaving ){
sl@0	4111	sqlite3DebugPrintf("%*s HAVING ", indent, "");
sl@0	4112	sqlite3PrintExpr(p->pHaving);
sl@0	4113	sqlite3DebugPrintf("\n");
sl@0	4114	}
sl@0	4115	if( p->pOrderBy ){
sl@0	4116	sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
sl@0	4117	sqlite3PrintExprList(p->pOrderBy);
sl@0	4118	sqlite3DebugPrintf("\n");
sl@0	4119	}
sl@0	4120	}
sl@0	4121	/* End of the structure debug printing code
sl@0	4122	*****************************************************************************/
sl@0	4123	#endif /* defined(SQLITE_TEST) \|\| defined(SQLITE_DEBUG) */

author	sl
	Tue, 10 Jun 2014 14:32:02 +0200
changeset 1	260cb5ec6c19
permissions	-rw-r--r--