xref: /sqlite-3.40.0/test/subselect.test (revision 74e4352a) 
1# 2001 September 15
2#
3# The author disclaims copyright to this source code.  In place of
4# a legal notice, here is a blessing:
5#
6#    May you do good and not evil.
7#    May you find forgiveness for yourself and forgive others.
8#    May you share freely, never taking more than you give.
9#
10#***********************************************************************
11# This file implements regression tests for SQLite library.  The
12# focus of this file is testing SELECT statements that are part of
13# expressions.
14#
15# $Id: subselect.test,v 1.13 2005/09/08 10:37:01 drh Exp $
16
17set testdir [file dirname $argv0]
18source $testdir/tester.tcl
19
20# Omit this whole file if the library is build without subquery support.
21ifcapable !subquery {
22  finish_test
23  return
24}
25
26# Basic sanity checking.  Try a simple subselect.
27#
28do_test subselect-1.1 {
29  execsql {
30    CREATE TABLE t1(a int, b int);
31    INSERT INTO t1 VALUES(1,2);
32    INSERT INTO t1 VALUES(3,4);
33    INSERT INTO t1 VALUES(5,6);
34  }
35  execsql {SELECT * FROM t1 WHERE a = (SELECT count(*) FROM t1)}
36} {3 4}
37
38# Try a select with more than one result column.
39#
40do_test subselect-1.2 {
41  set v [catch {execsql {SELECT * FROM t1 WHERE a = (SELECT * FROM t1)}} msg]
42  lappend v $msg
43} {1 {only a single result allowed for a SELECT that is part of an expression}}
44
45# A subselect without an aggregate.
46#
47do_test subselect-1.3a {
48  execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=2)}
49} {2}
50do_test subselect-1.3b {
51  execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=4)}
52} {4}
53do_test subselect-1.3c {
54  execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=6)}
55} {6}
56do_test subselect-1.3c {
57  execsql {SELECT b from t1 where a = (SELECT a FROM t1 WHERE b=8)}
58} {}
59
60# What if the subselect doesn't return any value.  We should get
61# NULL as the result.  Check it out.
62#
63do_test subselect-1.4 {
64  execsql {SELECT b from t1 where a = coalesce((SELECT a FROM t1 WHERE b=5),1)}
65} {2}
66
67# Try multiple subselects within a single expression.
68#
69do_test subselect-1.5 {
70  execsql {
71    CREATE TABLE t2(x int, y int);
72    INSERT INTO t2 VALUES(1,2);
73    INSERT INTO t2 VALUES(2,4);
74    INSERT INTO t2 VALUES(3,8);
75    INSERT INTO t2 VALUES(4,16);
76  }
77  execsql {
78    SELECT y from t2
79    WHERE x = (SELECT sum(b) FROM t1 where a notnull) - (SELECT sum(a) FROM t1)
80  }
81} {8}
82
83# Try something useful.  Delete every entry from t2 where the
84# x value is less than half of the maximum.
85#
86do_test subselect-1.6 {
87  execsql {DELETE FROM t2 WHERE x < 0.5*(SELECT max(x) FROM t2)}
88  execsql {SELECT x FROM t2 ORDER BY x}
89} {2 3 4}
90
91# Make sure sorting works for SELECTs there used as a scalar expression.
92#
93do_test subselect-2.1 {
94  execsql {
95    SELECT (SELECT a FROM t1 ORDER BY a), (SELECT a FROM t1 ORDER BY a DESC)
96  }
97} {1 5}
98do_test subselect-2.2 {
99  execsql {
100    SELECT 1 IN (SELECT a FROM t1 ORDER BY a);
101  }
102} {1}
103do_test subselect-2.3 {
104  execsql {
105    SELECT 2 IN (SELECT a FROM t1 ORDER BY a DESC);
106  }
107} {0}
108
109# Verify that the ORDER BY clause is honored in a subquery.
110#
111ifcapable compound {
112do_test subselect-3.1 {
113  execsql {
114    CREATE TABLE t3(x int);
115    INSERT INTO t3 SELECT a FROM t1 UNION ALL SELECT b FROM t1;
116    SELECT * FROM t3 ORDER BY x;
117  }
118} {1 2 3 4 5 6}
119} ;# ifcapable compound
120ifcapable !compound {
121do_test subselect-3.1 {
122  execsql {
123    CREATE TABLE t3(x int);
124    INSERT INTO t3 SELECT a FROM t1;
125    INSERT INTO t3 SELECT b FROM t1;
126    SELECT * FROM t3 ORDER BY x;
127  }
128} {1 2 3 4 5 6}
129} ;# ifcapable !compound
130
131do_test subselect-3.2 {
132  execsql {
133    SELECT sum(x) FROM (SELECT x FROM t3 ORDER BY x LIMIT 2);
134  }
135} {3}
136do_test subselect-3.3 {
137  execsql {
138    SELECT sum(x) FROM (SELECT x FROM t3 ORDER BY x DESC LIMIT 2);
139  }
140} {11}
141do_test subselect-3.4 {
142  execsql {
143    SELECT (SELECT x FROM t3 ORDER BY x);
144  }
145} {1}
146do_test subselect-3.5 {
147  execsql {
148    SELECT (SELECT x FROM t3 ORDER BY x DESC);
149  }
150} {6}
151do_test subselect-3.6 {
152  execsql {
153    SELECT (SELECT x FROM t3 ORDER BY x LIMIT 1);
154  }
155} {1}
156do_test subselect-3.7 {
157  execsql {
158    SELECT (SELECT x FROM t3 ORDER BY x DESC LIMIT 1);
159  }
160} {6}
161do_test subselect-3.8 {
162  execsql {
163    SELECT (SELECT x FROM t3 ORDER BY x LIMIT 1 OFFSET 2);
164  }
165} {3}
166do_test subselect-3.9 {
167  execsql {
168    SELECT (SELECT x FROM t3 ORDER BY x DESC LIMIT 1 OFFSET 2);
169  }
170} {4}
171do_test subselect-3.10 {
172  execsql {
173    SELECT x FROM t3 WHERE x IN
174       (SELECT x FROM t3 ORDER BY x DESC LIMIT 1 OFFSET 2);
175  }
176} {4}
177
178finish_test
179