1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
drop table if exists t1, t2;
select CASE "b" when "a" then 1 when "b" then 2 END;
CASE "b" when "a" then 1 when "b" then 2 END
2
select CASE "c" when "a" then 1 when "b" then 2 END;
CASE "c" when "a" then 1 when "b" then 2 END
NULL
select CASE "c" when "a" then 1 when "b" then 2 ELSE 3 END;
CASE "c" when "a" then 1 when "b" then 2 ELSE 3 END
3
select CASE BINARY "b" when "a" then 1 when "B" then 2 WHEN "b" then "ok" END;
CASE BINARY "b" when "a" then 1 when "B" then 2 WHEN "b" then "ok" END
ok
select CASE "b" when "a" then 1 when binary "B" then 2 WHEN "b" then "ok" END;
CASE "b" when "a" then 1 when binary "B" then 2 WHEN "b" then "ok" END
ok
select CASE concat("a","b") when concat("ab","") then "a" when "b" then "b" end;
CASE concat("a","b") when concat("ab","") then "a" when "b" then "b" end
a
select CASE when 1=0 then "true" else "false" END;
CASE when 1=0 then "true" else "false" END
false
select CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END;
CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END
one
explain extended select CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select (case 1 when 1 then 'one' when 2 then 'two' else 'more' end) AS "CASE 1 when 1 then ""one"" WHEN 2 then ""two"" ELSE ""more"" END"
select CASE 2.0 when 1 then "one" WHEN 2.0 then "two" ELSE "more" END;
CASE 2.0 when 1 then "one" WHEN 2.0 then "two" ELSE "more" END
two
select (CASE "two" when "one" then "1" WHEN "two" then "2" END) | 0;
(CASE "two" when "one" then "1" WHEN "two" then "2" END) | 0
2
select (CASE "two" when "one" then 1.00 WHEN "two" then 2.00 END) +0.0;
(CASE "two" when "one" then 1.00 WHEN "two" then 2.00 END) +0.0
2.00
select case 1/0 when "a" then "true" else "false" END;
case 1/0 when "a" then "true" else "false" END
false
select case 1/0 when "a" then "true" END;
case 1/0 when "a" then "true" END
NULL
select (case 1/0 when "a" then "true" END) | 0;
(case 1/0 when "a" then "true" END) | 0
NULL
select (case 1/0 when "a" then "true" END) + 0.0;
(case 1/0 when "a" then "true" END) + 0.0
NULL
select case when 1>0 then "TRUE" else "FALSE" END;
case when 1>0 then "TRUE" else "FALSE" END
TRUE
select case when 1<0 then "TRUE" else "FALSE" END;
case when 1<0 then "TRUE" else "FALSE" END
FALSE
create table t1 (a int);
insert into t1 values(1),(2),(3),(4);
select case a when 1 then 2 when 2 then 3 else 0 end as fcase, count(*) from t1 group by fcase;
fcase count(*)
0 2
2 1
3 1
explain extended select case a when 1 then 2 when 2 then 3 else 0 end as fcase, count(*) from t1 group by fcase;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 100.00 Using temporary; Using filesort
Warnings:
Note 1003 select (case "test"."t1"."a" when 1 then 2 when 2 then 3 else 0 end) AS "fcase",count(0) AS "count(*)" from "test"."t1" group by (case "test"."t1"."a" when 1 then 2 when 2 then 3 else 0 end)
select case a when 1 then "one" when 2 then "two" else "nothing" end as fcase, count(*) from t1 group by fcase;
fcase count(*)
nothing 2
one 1
two 1
drop table t1;
create table t1 (row int not null, col int not null, val varchar(255) not null);
insert into t1 values (1,1,'orange'),(1,2,'large'),(2,1,'yellow'),(2,2,'medium'),(3,1,'green'),(3,2,'small');
select max(case col when 1 then val else null end) as color from t1 group by row;
color
orange
yellow
green
drop table t1;
SET NAMES latin1;
CREATE TABLE t1 SELECT
CASE WHEN 1 THEN _latin1'a' COLLATE latin1_danish_ci ELSE _latin1'a' END AS c1,
CASE WHEN 1 THEN _latin1'a' ELSE _latin1'a' COLLATE latin1_danish_ci END AS c2,
CASE WHEN 1 THEN 'a' ELSE 1 END AS c3,
CASE WHEN 1 THEN 1 ELSE 'a' END AS c4,
CASE WHEN 1 THEN 'a' ELSE 1.0 END AS c5,
CASE WHEN 1 THEN 1.0 ELSE 'a' END AS c6,
CASE WHEN 1 THEN 1 ELSE 1.0 END AS c7,
CASE WHEN 1 THEN 1.0 ELSE 1 END AS c8,
CASE WHEN 1 THEN 1.0 END AS c9,
CASE WHEN 1 THEN 0.1e1 else 0.1 END AS c10,
CASE WHEN 1 THEN 0.1e1 else 1 END AS c11,
CASE WHEN 1 THEN 0.1e1 else '1' END AS c12
;
SHOW CREATE TABLE t1;
Table Create Table
t1 CREATE TABLE "t1" (
"c1" varchar(1) CHARACTER SET latin1 COLLATE latin1_danish_ci NOT NULL,
"c2" varchar(1) CHARACTER SET latin1 COLLATE latin1_danish_ci NOT NULL,
"c3" varbinary(1) NOT NULL,
"c4" varbinary(1) NOT NULL,
"c5" varbinary(4) NOT NULL,
"c6" varbinary(4) NOT NULL,
"c7" decimal(2,1) NOT NULL,
"c8" decimal(2,1) NOT NULL,
"c9" decimal(2,1),
"c10" double NOT NULL,
"c11" double NOT NULL,
"c12" varbinary(5) NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
DROP TABLE t1;
SELECT CASE
WHEN 1
THEN _latin1'a' COLLATE latin1_danish_ci
ELSE _latin1'a' COLLATE latin1_swedish_ci
END;
ERROR HY000: Illegal mix of collations (latin1_danish_ci,EXPLICIT) and (latin1_swedish_ci,EXPLICIT) for operation 'case'
SELECT CASE _latin1'a' COLLATE latin1_general_ci
WHEN _latin1'a' COLLATE latin1_danish_ci THEN 1
WHEN _latin1'a' COLLATE latin1_swedish_ci THEN 2
END;
ERROR HY000: Illegal mix of collations (latin1_general_ci,EXPLICIT), (latin1_danish_ci,EXPLICIT), (latin1_swedish_ci,EXPLICIT) for operation 'case'
SELECT
CASE _latin1'a' COLLATE latin1_general_ci WHEN _latin1'A' THEN '1' ELSE 2 END,
CASE _latin1'a' COLLATE latin1_bin WHEN _latin1'A' THEN '1' ELSE 2 END,
CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_swedish_ci THEN '1' ELSE 2 END,
CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_bin THEN '1' ELSE 2 END
;
CASE _latin1'a' COLLATE latin1_general_ci WHEN _latin1'A' THEN '1' ELSE 2 END CASE _latin1'a' COLLATE latin1_bin WHEN _latin1'A' THEN '1' ELSE 2 END CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_swedish_ci THEN '1' ELSE 2 END CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_bin THEN '1' ELSE 2 END
1 2 1 2
CREATE TABLE t1 SELECT COALESCE(_latin1'a',_latin2'a');
ERROR HY000: Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (latin2_general_ci,COERCIBLE) for operation 'coalesce'
CREATE TABLE t1 SELECT COALESCE('a' COLLATE latin1_swedish_ci,'b' COLLATE latin1_bin);
ERROR HY000: Illegal mix of collations (latin1_swedish_ci,EXPLICIT) and (latin1_bin,EXPLICIT) for operation 'coalesce'
CREATE TABLE t1 SELECT
COALESCE(1), COALESCE(1.0),COALESCE('a'),
COALESCE(1,1.0), COALESCE(1,'1'),COALESCE(1.1,'1'),
COALESCE('a' COLLATE latin1_bin,'b');
explain extended SELECT
COALESCE(1), COALESCE(1.0),COALESCE('a'),
COALESCE(1,1.0), COALESCE(1,'1'),COALESCE(1.1,'1'),
COALESCE('a' COLLATE latin1_bin,'b');
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select coalesce(1) AS "COALESCE(1)",coalesce(1.0) AS "COALESCE(1.0)",coalesce('a') AS "COALESCE('a')",coalesce(1,1.0) AS "COALESCE(1,1.0)",coalesce(1,'1') AS "COALESCE(1,'1')",coalesce(1.1,'1') AS "COALESCE(1.1,'1')",coalesce(('a' collate latin1_bin),'b') AS "COALESCE('a' COLLATE latin1_bin,'b')"
SHOW CREATE TABLE t1;
Table Create Table
t1 CREATE TABLE "t1" (
"COALESCE(1)" int(1) NOT NULL,
"COALESCE(1.0)" decimal(2,1) NOT NULL,
"COALESCE('a')" varchar(1) NOT NULL,
"COALESCE(1,1.0)" decimal(2,1) NOT NULL,
"COALESCE(1,'1')" varbinary(1) NOT NULL,
"COALESCE(1.1,'1')" varbinary(4) NOT NULL,
"COALESCE('a' COLLATE latin1_bin,'b')" varchar(1) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
DROP TABLE t1;
SELECT 'case+union+test'
UNION
SELECT CASE LOWER('1') WHEN LOWER('2') THEN 'BUG' ELSE 'nobug' END;
case+union+test
case+union+test
nobug
SELECT CASE LOWER('1') WHEN LOWER('2') THEN 'BUG' ELSE 'nobug' END;
CASE LOWER('1') WHEN LOWER('2') THEN 'BUG' ELSE 'nobug' END
nobug
SELECT 'case+union+test'
UNION
SELECT CASE '1' WHEN '2' THEN 'BUG' ELSE 'nobug' END;
case+union+test
case+union+test
nobug
create table t1(a float, b int default 3);
insert into t1 (a) values (2), (11), (8);
select min(a), min(case when 1=1 then a else NULL end),
min(case when 1!=1 then NULL else a end)
from t1 where b=3 group by b;
min(a) min(case when 1=1 then a else NULL end) min(case when 1!=1 then NULL else a end)
2 2 2
drop table t1;
CREATE TABLE t1 (EMPNUM INT);
INSERT INTO t1 VALUES (0), (2);
CREATE TABLE t2 (EMPNUM DECIMAL (4, 2));
INSERT INTO t2 VALUES (0.0), (9.0);
SELECT COALESCE(t2.EMPNUM,t1.EMPNUM) AS CEMPNUM,
t1.EMPNUM AS EMPMUM1, t2.EMPNUM AS EMPNUM2
FROM t1 LEFT JOIN t2 ON t1.EMPNUM=t2.EMPNUM;
CEMPNUM EMPMUM1 EMPNUM2
0.00 0 0.00
2.00 2 NULL
SELECT IFNULL(t2.EMPNUM,t1.EMPNUM) AS CEMPNUM,
t1.EMPNUM AS EMPMUM1, t2.EMPNUM AS EMPNUM2
FROM t1 LEFT JOIN t2 ON t1.EMPNUM=t2.EMPNUM;
CEMPNUM EMPMUM1 EMPNUM2
0.00 0 0.00
2.00 2 NULL
DROP TABLE t1,t2;
End of 4.1 tests
create table t1 (a int, b bigint unsigned);
create table t2 (c int);
insert into t1 (a, b) values (1,4572794622775114594), (2,18196094287899841997),
(3,11120436154190595086);
insert into t2 (c) values (1), (2), (3);
select t1.a, (case t1.a when 0 then 0 else t1.b end) d from t1
join t2 on t1.a=t2.c order by d;
a d
1 4572794622775114594
3 11120436154190595086
2 18196094287899841997
select t1.a, (case t1.a when 0 then 0 else t1.b end) d from t1
join t2 on t1.a=t2.c where b=11120436154190595086 order by d;
a d
3 11120436154190595086
drop table t1, t2;
End of 5.0 tests
|