# 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 1.13 2005/09/08 10:37:01 drh 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-1.3c {  execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=8)}} {}# 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 compoundifcapable !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 !compounddo_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}finish_test