Edit File: case.result
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#1 */ 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#1 */ 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 `fcase` 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 DEFAULT '', `c2` varchar(1) CHARACTER SET latin1 COLLATE latin1_danish_ci NOT NULL DEFAULT '', `c3` varchar(1) NOT NULL DEFAULT '', `c4` varchar(1) NOT NULL DEFAULT '', `c5` varchar(4) NOT NULL DEFAULT '', `c6` varchar(4) NOT NULL DEFAULT '', `c7` decimal(2,1) NOT NULL DEFAULT '0.0', `c8` decimal(2,1) NOT NULL DEFAULT '0.0', `c9` decimal(2,1) DEFAULT NULL, `c10` double NOT NULL DEFAULT '0', `c11` double NOT NULL DEFAULT '0', `c12` varchar(5) NOT NULL DEFAULT '' ) 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#1 */ 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 DEFAULT '0', `COALESCE(1.0)` decimal(2,1) NOT NULL DEFAULT '0.0', `COALESCE('a')` varchar(1) NOT NULL DEFAULT '', `COALESCE(1,1.0)` decimal(2,1) NOT NULL DEFAULT '0.0', `COALESCE(1,'1')` varchar(1) NOT NULL DEFAULT '', `COALESCE(1.1,'1')` varchar(4) NOT NULL DEFAULT '', `COALESCE('a' COLLATE latin1_bin,'b')` varchar(1) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT '' ) ENGINE=MyISAM DEFAULT CHARSET=latin1 DROP TABLE t1; CREATE TABLE t1 SELECT IFNULL('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 'ifnull' 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 CREATE TABLE t1(a YEAR); SELECT 1 FROM t1 WHERE a=1 AND CASE 1 WHEN a THEN 1 ELSE 1 END; 1 DROP TABLE t1; # # Bug#19875294 ASSERTION `SRC' FAILED IN MY_STRNXFRM_UNICODE # (SIG 6 -STRINGS/CTYPE-UTF8.C:5151) # set @@sql_mode=''; CREATE TABLE t1(c1 SET('','')CHARACTER SET ucs2) engine=innodb; Warnings: Note 1291 Column 'c1' has duplicated value '' in SET INSERT INTO t1 VALUES(990101.102); Warnings: Warning 1265 Data truncated for column 'c1' at row 1 SELECT COALESCE(c1)FROM t1 ORDER BY 1; COALESCE(c1) DROP TABLE t1; set @@sql_mode=default;