# 2001 September 15

 #

 # The author disclaims copyright to this source code.  In place of

 # a legal notice, here is a blessing:

 #

 #    May you do good and not evil.

 #    May you find forgiveness for yourself and forgive others.

 #    May you share freely, never taking more than you give.

 #

 #***********************************************************************

 # This file implements regression tests for SQLite library.  The

 # focus of this file is testing SELECT statements that are part of

 # expressions.

 #

 # $Id: subselect.test,v 1.16 2008/08/04 03:51:24 danielk1977 Exp $

 set testdir [file dirname $argv0]

 source $testdir/tester.tcl

 # Omit this whole file if the library is build without subquery support.

 ifcapable !subquery {

   finish_test

   return

 }

 # Basic sanity checking.  Try a simple subselect.

 #

 do_test subselect-1.1 {

   execsql {

     CREATE TABLE t1(a int, b int);

     INSERT INTO t1 VALUES(1,2);

     INSERT INTO t1 VALUES(3,4);

     INSERT INTO t1 VALUES(5,6);

   }

   execsql {SELECT * FROM t1 WHERE a = (SELECT count(*) FROM t1)}

 } {3 4}

 # Try a select with more than one result column.

 #

 do_test subselect-1.2 {

   set v [catch {execsql {SELECT * FROM t1 WHERE a = (SELECT * FROM t1)}} msg]

   lappend v $msg

 } {1 {only a single result allowed for a SELECT that is part of an expression}}

 # A subselect without an aggregate.

 #

 do_test subselect-1.3a {

   execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=2)}

 } {2}

 do_test subselect-1.3b {

   execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=4)}

 } {4}

 do_test subselect-1.3c {

   execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=6)}

 } {6}

 do_test subselect-1.3d {

   execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=8)}

 } {}

 ifcapable compound {

   do_test subselect-1.3e {

     execsql {

       SELECT b FROM t1

        WHERE a = (SELECT a FROM t1 UNION SELECT b FROM t1 ORDER BY 1);

     }

   } {2}

 }

 # What if the subselect doesn't return any value.  We should get

 # NULL as the result.  Check it out.

 #

 do_test subselect-1.4 {

   execsql {SELECT b from t1 where a = coalesce((SELECT a FROM t1 WHERE b=5),1)}

 } {2}

 # Try multiple subselects within a single expression.

 #

 do_test subselect-1.5 {

   execsql {

     CREATE TABLE t2(x int, y int);

     INSERT INTO t2 VALUES(1,2);

     INSERT INTO t2 VALUES(2,4);

     INSERT INTO t2 VALUES(3,8);

     INSERT INTO t2 VALUES(4,16);

   }

   execsql {

     SELECT y from t2 

     WHERE x = (SELECT sum(b) FROM t1 where a notnull) - (SELECT sum(a) FROM t1)

   }

 } {8}

 # Try something useful.  Delete every entry from t2 where the

 # x value is less than half of the maximum.

 #

 do_test subselect-1.6 {

   execsql {DELETE FROM t2 WHERE x < 0.5*(SELECT max(x) FROM t2)}

   execsql {SELECT x FROM t2 ORDER BY x}

 } {2 3 4}

 # Make sure sorting works for SELECTs there used as a scalar expression.

 #

 do_test subselect-2.1 {

   execsql {

     SELECT (SELECT a FROM t1 ORDER BY a), (SELECT a FROM t1 ORDER BY a DESC)

   }

 } {1 5}

 do_test subselect-2.2 {

   execsql {

     SELECT 1 IN (SELECT a FROM t1 ORDER BY a);

   }

 } {1}

 do_test subselect-2.3 {

   execsql {

     SELECT 2 IN (SELECT a FROM t1 ORDER BY a DESC);

   }

 } {0}

 # Verify that the ORDER BY clause is honored in a subquery.

 #

 ifcapable compound {

 do_test subselect-3.1 {

   execsql {

     CREATE TABLE t3(x int);

     INSERT INTO t3 SELECT a FROM t1 UNION ALL SELECT b FROM t1;

     SELECT * FROM t3 ORDER BY x;

   }

 } {1 2 3 4 5 6}

 } ;# ifcapable compound

 ifcapable !compound {

 do_test subselect-3.1 {

   execsql {

     CREATE TABLE t3(x int);

     INSERT INTO t3 SELECT a FROM t1; 

     INSERT INTO t3 SELECT b FROM t1;

     SELECT * FROM t3 ORDER BY x;

   }

 } {1 2 3 4 5 6}

 } ;# ifcapable !compound

 do_test subselect-3.2 {

   execsql {

     SELECT sum(x) FROM (SELECT x FROM t3 ORDER BY x LIMIT 2);

   }

 } {3}

 do_test subselect-3.3 {

   execsql {

     SELECT sum(x) FROM (SELECT x FROM t3 ORDER BY x DESC LIMIT 2);

   }

 } {11}

 do_test subselect-3.4 {

   execsql {

     SELECT (SELECT x FROM t3 ORDER BY x);

   }

 } {1}

 do_test subselect-3.5 {

   execsql {

     SELECT (SELECT x FROM t3 ORDER BY x DESC);

   }

 } {6}

 do_test subselect-3.6 {

   execsql {

     SELECT (SELECT x FROM t3 ORDER BY x LIMIT 1);

   }

 } {1}

 do_test subselect-3.7 {

   execsql {

     SELECT (SELECT x FROM t3 ORDER BY x DESC LIMIT 1);

   }

 } {6}

 do_test subselect-3.8 {

   execsql {

     SELECT (SELECT x FROM t3 ORDER BY x LIMIT 1 OFFSET 2);

   }

 } {3}

 do_test subselect-3.9 {

   execsql {

     SELECT (SELECT x FROM t3 ORDER BY x DESC LIMIT 1 OFFSET 2);

   }

 } {4}

 do_test subselect-3.10 {

   execsql {

     SELECT x FROM t3 WHERE x IN

        (SELECT x FROM t3 ORDER BY x DESC LIMIT 1 OFFSET 2);

   }

 } {4}

 # Ticket #2295.

 # Make sure type affinities work correctly on subqueries with

 # an ORDER BY clause.

 #

 do_test subselect-4.1 {

   execsql {

     CREATE TABLE t4(a TEXT, b TEXT);

     INSERT INTO t4 VALUES('a','1');

     INSERT INTO t4 VALUES('b','2');

     INSERT INTO t4 VALUES('c','3');

     SELECT a FROM t4 WHERE b IN (SELECT b FROM t4 ORDER BY b);

   }

 } {a b c}

 do_test subselect-4.2 {

   execsql {

     SELECT a FROM t4 WHERE b IN (SELECT b FROM t4 ORDER BY b LIMIT 1);

   }

 } {a}

 do_test subselect-4.3 {

   execsql {

     SELECT a FROM t4 WHERE b IN (SELECT b FROM t4 ORDER BY b DESC LIMIT 1);

   }

 } {c}

 finish_test