xref: /sqlite-3.40.0/test/null.test (revision c023e03e) 
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.
12#
13# This file implements tests for proper treatment of the special
14# value NULL.
15#
16
17set testdir [file dirname $argv0]
18source $testdir/tester.tcl
19
20# Create a table and some data to work with.
21#
22do_test null-1.0 {
23  execsql {
24    begin;
25    create table t1(a,b,c);
26    insert into t1 values(1,0,0);
27    insert into t1 values(2,0,1);
28    insert into t1 values(3,1,0);
29    insert into t1 values(4,1,1);
30    insert into t1 values(5,null,0);
31    insert into t1 values(6,null,1);
32    insert into t1 values(7,null,null);
33    commit;
34    select * from t1;
35  }
36} {1 0 0 2 0 1 3 1 0 4 1 1 5 {} 0 6 {} 1 7 {} {}}
37
38# Check for how arithmetic expressions handle NULL
39#
40do_test null-1.1 {
41  execsql {
42    select ifnull(a+b,99) from t1;
43  }
44} {1 2 4 5 99 99 99}
45do_test null-1.2 {
46  execsql {
47    select ifnull(b*c,99) from t1;
48  }
49} {0 0 0 1 99 99 99}
50
51# Check to see how the CASE expression handles NULL values.  The
52# first WHEN for which the test expression is TRUE is selected.
53# FALSE and UNKNOWN test expressions are skipped.
54#
55do_test null-2.1 {
56  execsql {
57    select ifnull(case when b<>0 then 1 else 0 end, 99) from t1;
58  }
59} {0 0 1 1 0 0 0}
60do_test null-2.2 {
61  execsql {
62    select ifnull(case when not b<>0 then 1 else 0 end, 99) from t1;
63  }
64} {1 1 0 0 0 0 0}
65do_test null-2.3 {
66  execsql {
67    select ifnull(case when b<>0 and c<>0 then 1 else 0 end, 99) from t1;
68  }
69} {0 0 0 1 0 0 0}
70do_test null-2.4 {
71  execsql {
72    select ifnull(case when not (b<>0 and c<>0) then 1 else 0 end, 99) from t1;
73  }
74} {1 1 1 0 1 0 0}
75do_test null-2.5 {
76  execsql {
77    select ifnull(case when b<>0 or c<>0 then 1 else 0 end, 99) from t1;
78  }
79} {0 1 1 1 0 1 0}
80do_test null-2.6 {
81  execsql {
82    select ifnull(case when not (b<>0 or c<>0) then 1 else 0 end, 99) from t1;
83  }
84} {1 0 0 0 0 0 0}
85do_test null-2.7 {
86  execsql {
87    select ifnull(case b when c then 1 else 0 end, 99) from t1;
88  }
89} {1 0 0 1 0 0 0}
90do_test null-2.8 {
91  execsql {
92    select ifnull(case c when b then 1 else 0 end, 99) from t1;
93  }
94} {1 0 0 1 0 0 0}
95
96# Check to see that NULL values are ignored in aggregate functions.
97#
98do_test null-3.1 {
99  execsql {
100    select count(*), count(b), count(c), sum(b), sum(c),
101           avg(b), avg(c), min(b), max(b) from t1;
102  }
103} {7 4 6 2 3 0.5 0.5 0 1}
104
105# Check to see how WHERE clauses handle NULL values.  A NULL value
106# is the same as UNKNOWN.  The WHERE clause should only select those
107# rows that are TRUE.  FALSE and UNKNOWN rows are rejected.
108#
109do_test null-4.1 {
110  execsql {
111    select a from t1 where b<10
112  }
113} {1 2 3 4}
114do_test null-4.2 {
115  execsql {
116    select a from t1 where not b>10
117  }
118} {1 2 3 4}
119do_test null-4.3 {
120  execsql {
121    select a from t1 where b<10 or c=1;
122  }
123} {1 2 3 4 6}
124do_test null-4.4 {
125  execsql {
126    select a from t1 where b<10 and c=1;
127  }
128} {2 4}
129do_test null-4.5 {
130  execsql {
131    select a from t1 where not (b<10 and c=1);
132  }
133} {1 3 5}
134
135# The DISTINCT keyword on a SELECT statement should treat NULL values
136# as distinct
137#
138do_test null-5.1 {
139  execsql {
140    select distinct b from t1 order by b;
141  }
142} {{} 0 1}
143
144# A UNION to two queries should treat NULL values
145# as distinct
146#
147do_test null-6.1 {
148  execsql {
149    select b from t1 union select c from t1 order by c;
150  }
151} {{} 0 1}
152
153# The UNIQUE constraint only applies to non-null values
154#
155do_test null-7.1 {
156  execsql {
157    create table t2(a, b unique on conflict ignore);
158    insert into t2 values(1,1);
159    insert into t2 values(2,null);
160    insert into t2 values(3,null);
161    insert into t2 values(4,1);
162    select a from t2;
163  }
164} {1 2 3}
165do_test null-7.2 {
166  execsql {
167    create table t3(a, b, c, unique(b,c) on conflict ignore);
168    insert into t3 values(1,1,1);
169    insert into t3 values(2,null,1);
170    insert into t3 values(3,null,1);
171    insert into t3 values(4,1,1);
172    select a from t3;
173  }
174} {1 2 3}
175
176
177
178finish_test
179