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drop table if exists t1,t2,t3; CREATE TABLE t1 (id int,facility char(20)); CREATE TABLE t2 (facility char(20)); INSERT INTO t1 VALUES (NULL,NULL); INSERT INTO t1 VALUES (-1,''); INSERT INTO t1 VALUES (0,''); INSERT INTO t1 VALUES (1,'/L'); INSERT INTO t1 VALUES (2,'A01'); INSERT INTO t1 VALUES (3,'ANC'); INSERT INTO t1 VALUES (4,'F01'); INSERT INTO t1 VALUES (5,'FBX'); INSERT INTO t1 VALUES (6,'MT'); INSERT INTO t1 VALUES (7,'P'); INSERT INTO t1 VALUES (8,'RV'); INSERT INTO t1 VALUES (9,'SRV'); INSERT INTO t1 VALUES (10,'VMT'); INSERT INTO t2 SELECT DISTINCT FACILITY FROM t1; select id from t1 group by id; id NULL -1 0 1 2 3 4 5 6 7 8 9 10 select * from t1 order by id; id facility NULL NULL -1 0 1 /L 2 A01 3 ANC 4 F01 5 FBX 6 MT 7 P 8 RV 9 SRV 10 VMT select id-5,facility from t1 order by "id-5"; id-5 facility NULL NULL -6 -5 -4 /L -3 A01 -2 ANC -1 F01 0 FBX 1 MT 2 P 3 RV 4 SRV 5 VMT select id,concat(facility) from t1 group by id ; id concat(facility) NULL NULL -1 0 1 /L 2 A01 3 ANC 4 F01 5 FBX 6 MT 7 P 8 RV 9 SRV 10 VMT select id+0 as a,max(id),concat(facility) as b from t1 group by a order by b desc,a; a max(id) b 10 10 VMT 9 9 SRV 8 8 RV 7 7 P 6 6 MT 5 5 FBX 4 4 F01 3 3 ANC 2 2 A01 1 1 /L -1 -1 0 0 NULL NULL NULL select id >= 0 and id <= 5 as grp,count(*) from t1 group by grp; grp count(*) NULL 1 0 6 1 6 SELECT DISTINCT FACILITY FROM t1; FACILITY NULL /L A01 ANC F01 FBX MT P RV SRV VMT SELECT FACILITY FROM t2; FACILITY NULL /L A01 ANC F01 FBX MT P RV SRV VMT SELECT count(*) from t1,t2 where t1.facility=t2.facility; count(*) 12 select count(facility) from t1; count(facility) 12 select count(*) from t1; count(*) 13 select count(*) from t1 where facility IS NULL; count(*) 1 select count(*) from t1 where facility = NULL; count(*) 0 select count(*) from t1 where facility IS NOT NULL; count(*) 12 select count(*) from t1 where id IS NULL; count(*) 1 select count(*) from t1 where id IS NOT NULL; count(*) 12 drop table t1,t2; CREATE TABLE t1 (UserId int(11) DEFAULT '0' NOT NULL); INSERT INTO t1 VALUES (20); INSERT INTO t1 VALUES (27); SELECT UserId FROM t1 WHERE Userid=22; UserId SELECT UserId FROM t1 WHERE UserId=22 group by Userid; UserId SELECT DISTINCT UserId FROM t1 WHERE UserId=22 group by Userid; UserId SELECT DISTINCT UserId FROM t1 WHERE UserId=22; UserId drop table t1; CREATE TABLE t1 (a int(10) unsigned not null primary key,b int(10) unsigned); INSERT INTO t1 VALUES (1,1),(2,1),(3,1),(4,1); CREATE TABLE t2 (a int(10) unsigned not null, key (A)); INSERT INTO t2 VALUES (1),(2); CREATE TABLE t3 (a int(10) unsigned, key(A), b text); INSERT INTO t3 VALUES (1,'1'),(2,'2'); SELECT DISTINCT t3.b FROM t3,t2,t1 WHERE t3.a=t1.b AND t1.a=t2.a; b 1 INSERT INTO t2 values (1),(2),(3); INSERT INTO t3 VALUES (1,'1'),(2,'2'),(1,'1'),(2,'2'); explain SELECT distinct t3.a FROM t3,t2,t1 WHERE t3.a=t1.b AND t1.a=t2.a; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL index a a 4 NULL 5 100.00 Using index; Using temporary 1 SIMPLE t1 NULL eq_ref PRIMARY PRIMARY 4 test.t2.a 1 100.00 Using where 1 SIMPLE t3 NULL ref a a 5 test.t1.b 2 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t3`.`a` AS `a` from `test`.`t3` join `test`.`t2` join `test`.`t1` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t3`.`a` = `test`.`t1`.`b`)) SELECT distinct t3.a FROM t3,t2,t1 WHERE t3.a=t1.b AND t1.a=t2.a; a 1 create temporary table t4 select * from t3; insert into t3 select * from t4; insert into t4 select * from t3; insert into t3 select * from t4; insert into t4 select * from t3; insert into t3 select * from t4; insert into t4 select * from t3; insert into t3 select * from t4; ANALYZE TABLE t1,t2,t3; Table Op Msg_type Msg_text test.t1 analyze status OK test.t2 analyze status OK test.t3 analyze status OK explain select distinct t1.a from t1,t3 where t1.a=t3.a; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 4 NULL 4 100.00 Using index; Using temporary 1 SIMPLE t3 NULL ref a a 5 test.t1.a 102 100.00 Using index; Distinct Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a` from `test`.`t1` join `test`.`t3` where (`test`.`t3`.`a` = `test`.`t1`.`a`) flush status; select distinct t1.a from t1,t3 where t1.a=t3.a; a 1 2 show status like 'Handler_read%'; Variable_name Value Handler_read_first 1 Handler_read_key 4 Handler_read_last 0 Handler_read_next 4 Handler_read_prev 0 Handler_read_rnd 0 Handler_read_rnd_next 3 flush status; select distinct 1 from t1,t3 where t1.a=t3.a; 1 1 show status like 'Handler_read%'; Variable_name Value Handler_read_first 1 Handler_read_key 4 Handler_read_last 0 Handler_read_next 208 Handler_read_prev 0 Handler_read_rnd 0 Handler_read_rnd_next 1 explain SELECT distinct t1.a from t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 4 NULL 4 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a` from `test`.`t1` explain SELECT distinct t1.a from t1 order by a desc; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 4 NULL 4 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a` from `test`.`t1` order by `test`.`t1`.`a` desc explain SELECT t1.a from t1 group by a order by a desc; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 4 NULL 4 100.00 Using index Warnings: Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` group by `test`.`t1`.`a` desc order by `test`.`t1`.`a` desc explain SELECT distinct t1.a from t1 order by a desc limit 1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 4 NULL 1 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a` from `test`.`t1` order by `test`.`t1`.`a` desc limit 1 explain SELECT distinct a from t3 order by a desc limit 2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t3 NULL index a a 5 NULL 204 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t3`.`a` AS `a` from `test`.`t3` order by `test`.`t3`.`a` desc limit 2 explain SELECT distinct a,b from t3 order by a+1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t3 NULL ALL NULL NULL NULL NULL 204 100.00 Using temporary; Using filesort Warnings: Note 1003 /* select#1 */ select distinct `test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b` from `test`.`t3` order by (`test`.`t3`.`a` + 1) explain SELECT distinct a,b from t3 order by a limit 2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t3 NULL index NULL a 5 NULL 2 100.00 Using temporary Warnings: Note 1003 /* select#1 */ select distinct `test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b` from `test`.`t3` order by `test`.`t3`.`a` limit 2 explain SELECT a,b from t3 group by a,b order by a+1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t3 NULL ALL NULL NULL NULL NULL 204 100.00 Using temporary; Using filesort Warnings: Note 1003 /* select#1 */ select `test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b` from `test`.`t3` group by `test`.`t3`.`a`,`test`.`t3`.`b` order by (`test`.`t3`.`a` + 1) SELECT distinct t1.a from t1; a 1 2 3 4 SELECT distinct t1.a from t1 order by a desc; a 4 3 2 1 SELECT t1.a from t1 group by a order by a desc; a 4 3 2 1 SELECT distinct t1.a from t1 order by a desc limit 1; a 4 SELECT distinct a from t3 order by a desc limit 2; a 2 1 SELECT distinct a,b from t3 order by a+1; a b 1 1 2 2 SELECT distinct a,b from t3 order by a limit 2; a b 1 1 2 2 SELECT a,b from t3 group by a,b order by a+1; a b 1 1 2 2 drop table t1,t2,t3,t4; CREATE TABLE t1 (name varchar(255)); INSERT INTO t1 VALUES ('aa'),('ab'),('ac'),('ad'),('ae'); SELECT DISTINCT * FROM t1 LIMIT 2; name aa ab SELECT DISTINCT name FROM t1 LIMIT 2; name aa ab SELECT DISTINCT 1 FROM t1 LIMIT 2; 1 1 drop table t1; CREATE TABLE t1 ( ID int(11) NOT NULL auto_increment, NAME varchar(75) DEFAULT '' NOT NULL, LINK_ID int(11) DEFAULT '0' NOT NULL, PRIMARY KEY (ID), KEY NAME (NAME), KEY LINK_ID (LINK_ID) ); INSERT INTO t1 (ID, NAME, LINK_ID) VALUES (1,'Mike',0),(2,'Jack',0),(3,'Bill',0); CREATE TABLE t2 ( ID int(11) NOT NULL auto_increment, NAME varchar(150) DEFAULT '' NOT NULL, PRIMARY KEY (ID), KEY NAME (NAME) ); SELECT DISTINCT t2.id AS key_link_id, t2.name AS link FROM t1 LEFT JOIN t2 ON t1.link_id=t2.id GROUP BY t1.id ORDER BY link; key_link_id link NULL NULL drop table t1,t2; create table t1 ( id int not null, name tinytext not null, unique (id) ); create table t2 ( id int not null, idx int not null, unique (id, idx) ); create table t3 ( id int not null, idx int not null, unique (id, idx) ); insert into t1 values (1,'yes'), (2,'no'); insert into t2 values (1,1); insert into t3 values (1,1); EXPLAIN SELECT DISTINCT t1.id from t1 straight_join t2 straight_join t3 straight_join t1 as j_lj_t2 left join t2 as t2_lj on j_lj_t2.id=t2_lj.id straight_join t1 as j_lj_t3 left join t3 as t3_lj on j_lj_t3.id=t3_lj.id WHERE ((t1.id=j_lj_t2.id AND t2_lj.id IS NULL) OR (t1.id=t2.id AND t2.idx=2)) AND ((t1.id=j_lj_t3.id AND t3_lj.id IS NULL) OR (t1.id=t3.id AND t3.idx=2)); id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index id id 4 NULL 2 100.00 Using index; Using temporary 1 SIMPLE t2 NULL index id id 8 NULL 1 100.00 Using index; Distinct; Using join buffer (Block Nested Loop) 1 SIMPLE t3 NULL index id id 8 NULL 1 100.00 Using index; Distinct; Using join buffer (Block Nested Loop) 1 SIMPLE j_lj_t2 NULL index id id 4 NULL 2 100.00 Using where; Using index; Distinct; Using join buffer (Block Nested Loop) 1 SIMPLE t2_lj NULL index id id 8 NULL 1 100.00 Using where; Using index; Distinct; Using join buffer (Block Nested Loop) 1 SIMPLE j_lj_t3 NULL index id id 4 NULL 2 100.00 Using where; Using index; Distinct; Using join buffer (Block Nested Loop) 1 SIMPLE t3_lj NULL index id id 8 NULL 1 100.00 Using where; Using index; Distinct; Using join buffer (Block Nested Loop) Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`id` AS `id` from `test`.`t1` straight_join `test`.`t2` straight_join `test`.`t3` straight_join `test`.`t1` `j_lj_t2` left join `test`.`t2` `t2_lj` on((`test`.`t2_lj`.`id` = `test`.`j_lj_t2`.`id`)) straight_join `test`.`t1` `j_lj_t3` left join `test`.`t3` `t3_lj` on((`test`.`t3_lj`.`id` = `test`.`j_lj_t3`.`id`)) where ((((`test`.`j_lj_t2`.`id` = `test`.`t1`.`id`) and isnull(`test`.`t2_lj`.`id`)) or ((`test`.`t2`.`idx` = 2) and (`test`.`t2`.`id` = `test`.`t1`.`id`))) and (((`test`.`j_lj_t3`.`id` = `test`.`t1`.`id`) and isnull(`test`.`t3_lj`.`id`)) or ((`test`.`t3`.`idx` = 2) and (`test`.`t3`.`id` = `test`.`t1`.`id`)))) SELECT DISTINCT t1.id from t1 straight_join t2 straight_join t3 straight_join t1 as j_lj_t2 left join t2 as t2_lj on j_lj_t2.id=t2_lj.id straight_join t1 as j_lj_t3 left join t3 as t3_lj on j_lj_t3.id=t3_lj.id WHERE ((t1.id=j_lj_t2.id AND t2_lj.id IS NULL) OR (t1.id=t2.id AND t2.idx=2)) AND ((t1.id=j_lj_t3.id AND t3_lj.id IS NULL) OR (t1.id=t3.id AND t3.idx=2)); id 2 drop table t1,t2,t3; create table t1 (a int not null, b int not null, t time); insert into t1 values (1,1,"00:06:15"),(1,2,"00:06:15"),(1,2,"00:30:15"),(1,3,"00:06:15"),(1,3,"00:30:15"); select a,sec_to_time(sum(time_to_sec(t))) from t1 group by a,b; a sec_to_time(sum(time_to_sec(t))) 1 00:06:15 1 00:36:30 1 00:36:30 select distinct a,sec_to_time(sum(time_to_sec(t))) from t1 group by a,b; a sec_to_time(sum(time_to_sec(t))) 1 00:06:15 1 00:36:30 create table t2 (a int not null primary key, b int); insert into t2 values (1,1),(2,2),(3,3); select t1.a,sec_to_time(sum(time_to_sec(t))) from t1 left join t2 on (t1.b=t2.a) group by t1.a,t2.b; a sec_to_time(sum(time_to_sec(t))) 1 00:06:15 1 00:36:30 1 00:36:30 select distinct t1.a,sec_to_time(sum(time_to_sec(t))) from t1 left join t2 on (t1.b=t2.a) group by t1.a,t2.b; a sec_to_time(sum(time_to_sec(t))) 1 00:06:15 1 00:36:30 drop table t1,t2; create table t1 (a int not null,b char(5), c text); insert into t1 (a) values (1),(2),(3),(4),(1),(2),(3),(4); select distinct a from t1 group by b,a having a > 2 order by a desc; a 4 3 select distinct a,c from t1 group by b,c,a having a > 2 order by a desc; a c 4 NULL 3 NULL drop table t1; create table t1 (a char(1), key(a)) engine=myisam; insert into t1 values('1'),('1'); select * from t1 where a >= '1'; a 1 1 select distinct a from t1 order by a desc; a 1 select distinct a from t1 where a >= '1' order by a desc; a 1 drop table t1; CREATE TABLE t1 (email varchar(50), infoID BIGINT, dateentered DATETIME); CREATE TABLE t2 (infoID BIGINT, shipcode varchar(10)); INSERT INTO t1 (email, infoID, dateentered) VALUES ('test1@testdomain.com', 1, '2002-07-30 22:56:38'), ('test1@testdomain.com', 1, '2002-07-27 22:58:16'), ('test2@testdomain.com', 1, '2002-06-19 15:22:19'), ('test2@testdomain.com', 2, '2002-06-18 14:23:47'), ('test3@testdomain.com', 1, '2002-05-19 22:17:32'); INSERT INTO t2(infoID, shipcode) VALUES (1, 'Z001'), (2, 'R002'); SELECT DISTINCTROW email, shipcode FROM t1, t2 WHERE t1.infoID=t2.infoID; email shipcode test1@testdomain.com Z001 test2@testdomain.com Z001 test2@testdomain.com R002 test3@testdomain.com Z001 SELECT DISTINCTROW email FROM t1 ORDER BY dateentered DESC; email test1@testdomain.com test2@testdomain.com test3@testdomain.com SELECT DISTINCTROW email, shipcode FROM t1, t2 WHERE t1.infoID=t2.infoID ORDER BY dateentered DESC; email shipcode test1@testdomain.com Z001 test2@testdomain.com Z001 test2@testdomain.com R002 test3@testdomain.com Z001 drop table t1,t2; SET sql_mode = 'NO_ENGINE_SUBSTITUTION'; Warnings: Warning 3090 Changing sql mode 'NO_AUTO_CREATE_USER' is deprecated. It will be removed in a future release. CREATE TABLE t1 (privatemessageid int(10) unsigned NOT NULL auto_increment, folderid smallint(6) NOT NULL default '0', userid int(10) unsigned NOT NULL default '0', touserid int(10) unsigned NOT NULL default '0', fromuserid int(10) unsigned NOT NULL default '0', title varchar(250) NOT NULL default '', message mediumtext NOT NULL, dateline int(10) unsigned NOT NULL default '0', showsignature smallint(6) NOT NULL default '0', iconid smallint(5) unsigned NOT NULL default '0', messageread smallint(6) NOT NULL default '0', readtime int(10) unsigned NOT NULL default '0', receipt smallint(6) unsigned NOT NULL default '0', deleteprompt smallint(6) unsigned NOT NULL default '0', multiplerecipients smallint(6) unsigned NOT NULL default '0', PRIMARY KEY (privatemessageid), KEY userid (userid)) ENGINE=MyISAM; INSERT INTO t1 VALUES (128,0,33,33,8,':D','',996121863,1,0,2,996122850,2,0,0); CREATE TABLE t2 (userid int(10) unsigned NOT NULL auto_increment, usergroupid smallint(5) unsigned NOT NULL default '0', username varchar(50) NOT NULL default '', password varchar(50) NOT NULL default '', email varchar(50) NOT NULL default '', styleid smallint(5) unsigned NOT NULL default '0', parentemail varchar(50) NOT NULL default '', coppauser smallint(6) NOT NULL default '0', homepage varchar(100) NOT NULL default '', icq varchar(20) NOT NULL default '', aim varchar(20) NOT NULL default '', yahoo varchar(20) NOT NULL default '', signature mediumtext NOT NULL, adminemail smallint(6) NOT NULL default '0', showemail smallint(6) NOT NULL default '0', invisible smallint(6) NOT NULL default '0', usertitle varchar(250) NOT NULL default '', customtitle smallint(6) NOT NULL default '0', joindate int(10) unsigned NOT NULL default '0', cookieuser smallint(6) NOT NULL default '0', daysprune smallint(6) NOT NULL default '0', lastvisit int(10) unsigned NOT NULL default '0', lastactivity int(10) unsigned NOT NULL default '0', lastpost int(10) unsigned NOT NULL default '0', posts smallint(5) unsigned NOT NULL default '0', timezoneoffset varchar(4) NOT NULL default '', emailnotification smallint(6) NOT NULL default '0', buddylist mediumtext NOT NULL, ignorelist mediumtext NOT NULL, pmfolders mediumtext NOT NULL, receivepm smallint(6) NOT NULL default '0', emailonpm smallint(6) NOT NULL default '0', pmpopup smallint(6) NOT NULL default '0', avatarid smallint(6) NOT NULL default '0', avatarrevision int(6) unsigned NOT NULL default '0', options smallint(6) NOT NULL default '15', birthday date NOT NULL default '0000-00-00', maxposts smallint(6) NOT NULL default '-1', startofweek smallint(6) NOT NULL default '1', ipaddress varchar(20) NOT NULL default '', referrerid int(10) unsigned NOT NULL default '0', nosessionhash smallint(6) NOT NULL default '0', autorefresh smallint(6) NOT NULL default '-1', messagepopup tinyint(2) NOT NULL default '0', inforum smallint(5) unsigned NOT NULL default '0', ratenum smallint(5) unsigned NOT NULL default '0', ratetotal smallint(5) unsigned NOT NULL default '0', allowrate smallint(5) unsigned NOT NULL default '1', PRIMARY KEY (userid), KEY usergroupid (usergroupid), KEY username (username), KEY inforum (inforum)) ENGINE=MyISAM; INSERT INTO t2 VALUES (33,6,'Kevin','0','kevin@stileproject.com',1,'',0,'http://www.stileproject.com','','','','',1,1,0,'Administrator',0,996120694,1,-1,1030996168,1031027028,1030599436,36,'-6',0,'','','',1,0,1,0,0,15,'0000-00-00',-1,1,'64.0.0.0',0,1,-1,0,0,4,19,1); SELECT DISTINCT t1.*, t2.* FROM t1 LEFT JOIN t2 ON (t2.userid = t1.touserid); privatemessageid folderid userid touserid fromuserid title message dateline showsignature iconid messageread readtime receipt deleteprompt multiplerecipients userid usergroupid username password email styleid parentemail coppauser homepage icq aim yahoo signature adminemail showemail invisible usertitle customtitle joindate cookieuser daysprune lastvisit lastactivity lastpost posts timezoneoffset emailnotification buddylist ignorelist pmfolders receivepm emailonpm pmpopup avatarid avatarrevision options birthday maxposts startofweek ipaddress referrerid nosessionhash autorefresh messagepopup inforum ratenum ratetotal allowrate 128 0 33 33 8 :D 996121863 1 0 2 996122850 2 0 0 33 6 Kevin 0 kevin@stileproject.com 1 0 http://www.stileproject.com 1 1 0 Administrator 0 996120694 1 -1 1030996168 1031027028 1030599436 36 -6 0 1 0 1 0 0 15 0000-00-00 -1 1 64.0.0.0 0 1 -1 0 0 4 19 1 DROP TABLE t1,t2; SET sql_mode = default; CREATE TABLE t1 (a int primary key, b int, c int); INSERT t1 VALUES (1,2,3); CREATE TABLE t2 (a int primary key, b int, c int); INSERT t2 VALUES (3,4,5); SELECT DISTINCT t1.a, t2.b FROM t1, t2 WHERE t1.a=1 ORDER BY t2.c; a b 1 4 DROP TABLE t1,t2; CREATE table t1 ( `id` int(11) NOT NULL auto_increment, `name` varchar(50) NOT NULL default '', PRIMARY KEY (`id`)) ENGINE=MyISAM AUTO_INCREMENT=3 ; INSERT INTO t1 VALUES (1, 'aaaaa'); INSERT INTO t1 VALUES (3, 'aaaaa'); INSERT INTO t1 VALUES (2, 'eeeeeee'); select distinct left(name,1) as name from t1; name a e drop table t1; CREATE TABLE t1 ( ID int(11) NOT NULL auto_increment, NAME varchar(75) DEFAULT '' NOT NULL, LINK_ID int(11) DEFAULT '0' NOT NULL, PRIMARY KEY (ID), KEY NAME (NAME), KEY LINK_ID (LINK_ID) ); INSERT INTO t1 (ID, NAME, LINK_ID) VALUES (1,'Mike',0); INSERT INTO t1 (ID, NAME, LINK_ID) VALUES (2,'Jack',0); INSERT INTO t1 (ID, NAME, LINK_ID) VALUES (3,'Bill',0); CREATE TABLE t2 ( ID int(11) NOT NULL auto_increment, NAME varchar(150) DEFAULT '' NOT NULL, PRIMARY KEY (ID), KEY NAME (NAME) ); SELECT DISTINCT t2.id AS key_link_id, t2.name AS link FROM t1 LEFT JOIN t2 ON t1.link_id=t2.id GROUP BY t1.id ORDER BY link; key_link_id link NULL NULL drop table t1,t2; CREATE TABLE t1 ( html varchar(5) default NULL, rin int(11) default '0', rout int(11) default '0' ) ENGINE=MyISAM; INSERT INTO t1 VALUES ('1',1,0); SELECT DISTINCT html,SUM(rout)/(SUM(rin)+1) as 'prod' FROM t1 GROUP BY rin; html prod 1 0.0000 drop table t1; CREATE TABLE t1 (a int); INSERT INTO t1 VALUES (1),(2),(3),(4),(5); SELECT DISTINCT a, 1 FROM t1; a 1 1 1 2 1 3 1 4 1 5 1 SELECT DISTINCT 1, a FROM t1; 1 a 1 1 1 2 1 3 1 4 1 5 CREATE TABLE t2 (a int, b int); INSERT INTO t2 VALUES (1,1),(2,2),(2,3),(2,4),(3,5); SELECT DISTINCT a, b, 2 FROM t2; a b 2 1 1 2 2 2 2 2 3 2 2 4 2 3 5 2 SELECT DISTINCT 2, a, b FROM t2; 2 a b 2 1 1 2 2 2 2 2 3 2 2 4 2 3 5 SELECT DISTINCT a, 2, b FROM t2; a 2 b 1 2 1 2 2 2 2 2 3 2 2 4 3 2 5 DROP TABLE t1,t2; CREATE TABLE t1(a INT PRIMARY KEY, b INT); INSERT INTO t1 VALUES (1,1), (2,1), (3,1); EXPLAIN SELECT DISTINCT a FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 4 NULL 3 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a` from `test`.`t1` EXPLAIN SELECT DISTINCT a,b FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 3 100.00 NULL Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` EXPLAIN SELECT DISTINCT t1_1.a, t1_1.b FROM t1 t1_1, t1 t1_2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1_1 NULL ALL NULL NULL NULL NULL 3 100.00 Using temporary 1 SIMPLE t1_2 NULL index NULL PRIMARY 4 NULL 3 100.00 Using index; Distinct; Using join buffer (Block Nested Loop) Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1_1`.`a` AS `a`,`test`.`t1_1`.`b` AS `b` from `test`.`t1` `t1_1` join `test`.`t1` `t1_2` EXPLAIN SELECT DISTINCT t1_1.a, t1_1.b FROM t1 t1_1, t1 t1_2 WHERE t1_1.a = t1_2.a; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1_1 NULL ALL PRIMARY NULL NULL NULL 3 100.00 Using temporary 1 SIMPLE t1_2 NULL eq_ref PRIMARY PRIMARY 4 test.t1_1.a 1 100.00 Using index; Distinct Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1_1`.`a` AS `a`,`test`.`t1_1`.`b` AS `b` from `test`.`t1` `t1_1` join `test`.`t1` `t1_2` where (`test`.`t1_2`.`a` = `test`.`t1_1`.`a`) EXPLAIN SELECT a FROM t1 GROUP BY a; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 4 NULL 3 100.00 Using index Warnings: Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` group by `test`.`t1`.`a` EXPLAIN SELECT a,b FROM t1 GROUP BY a,b; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 3 100.00 Using filesort Warnings: Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` group by `test`.`t1`.`a`,`test`.`t1`.`b` EXPLAIN SELECT DISTINCT a,b FROM t1 GROUP BY a,b; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 3 100.00 Using filesort Warnings: Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` group by `test`.`t1`.`a`,`test`.`t1`.`b` CREATE TABLE t2(a INT, b INT NOT NULL, c INT NOT NULL, d INT, PRIMARY KEY (a,b)); INSERT INTO t2 VALUES (1,1,1,50), (1,2,3,40), (2,1,3,4); EXPLAIN SELECT DISTINCT a FROM t2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL index PRIMARY PRIMARY 8 NULL 3 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t2`.`a` AS `a` from `test`.`t2` EXPLAIN SELECT DISTINCT a,a FROM t2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL index PRIMARY PRIMARY 8 NULL 3 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t2`.`a` AS `a`,`test`.`t2`.`a` AS `a` from `test`.`t2` EXPLAIN SELECT DISTINCT b,a FROM t2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL index PRIMARY PRIMARY 8 NULL 3 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t2`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t2` EXPLAIN SELECT DISTINCT a,c FROM t2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 3 100.00 Using temporary Warnings: Note 1003 /* select#1 */ select distinct `test`.`t2`.`a` AS `a`,`test`.`t2`.`c` AS `c` from `test`.`t2` EXPLAIN SELECT DISTINCT c,a,b FROM t2; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 3 100.00 NULL Warnings: Note 1003 /* select#1 */ select distinct `test`.`t2`.`c` AS `c`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` EXPLAIN SELECT DISTINCT a,b,d FROM t2 GROUP BY c,b,d; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 3 100.00 Using temporary; Using filesort Warnings: Note 1003 /* select#1 */ select distinct `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`d` AS `d` from `test`.`t2` group by `test`.`t2`.`c`,`test`.`t2`.`b`,`test`.`t2`.`d` CREATE UNIQUE INDEX c_b_unq ON t2 (c,b); EXPLAIN SELECT DISTINCT a,b,d FROM t2 GROUP BY c,b,d; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 3 100.00 Using filesort Warnings: Note 1003 /* select#1 */ select distinct `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`d` AS `d` from `test`.`t2` group by `test`.`t2`.`c`,`test`.`t2`.`b`,`test`.`t2`.`d` DROP TABLE t1,t2; create table t1 (id int, dsc varchar(50)); insert into t1 values (1, "line number one"), (2, "line number two"), (3, "line number three"); select distinct id, IFNULL(dsc, '-') from t1; id IFNULL(dsc, '-') 1 line number one 2 line number two 3 line number three drop table t1; CREATE TABLE t1 (a int primary key, b int); INSERT INTO t1 (a,b) values (1,1), (2,3), (3,2); explain SELECT DISTINCT a, b FROM t1 ORDER BY b; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 3 100.00 Using filesort Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` order by `test`.`t1`.`b` SELECT DISTINCT a, b FROM t1 ORDER BY b; a b 1 1 3 2 2 3 DROP TABLE t1; CREATE TABLE t1 ( ID int(11) NOT NULL auto_increment, x varchar(20) default NULL, y decimal(10,0) default NULL, PRIMARY KEY (ID), KEY (y) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; INSERT INTO t1 VALUES (1,'ba','-1'), (2,'ba','1150'), (306,'ba','-1'), (307,'ba','1150'), (611,'ba','-1'), (612,'ba','1150'); select count(distinct x,y) from t1; count(distinct x,y) 2 select count(distinct concat(x,y)) from t1; count(distinct concat(x,y)) 2 drop table t1; CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a,b)); INSERT INTO t1 VALUES (1, 101); INSERT INTO t1 SELECT a + 1, a + 101 FROM t1; INSERT INTO t1 SELECT a + 2, a + 102 FROM t1; INSERT INTO t1 SELECT a + 4, a + 104 FROM t1; INSERT INTO t1 SELECT a + 8, a + 108 FROM t1; EXPLAIN SELECT DISTINCT a,a FROM t1 WHERE b < 12 ORDER BY a; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY PRIMARY 8 NULL 16 33.33 Using where; Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a`,`test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`b` < 12) order by `test`.`t1`.`a` SELECT DISTINCT a,a FROM t1 WHERE b < 12 ORDER BY a; a a DROP TABLE t1; DROP TABLE IF EXISTS t1; CREATE TABLE t1 (id INT NOT NULL, fruit_id INT NOT NULL, fruit_name varchar(20) default NULL); INSERT INTO t1 VALUES (1,1,'ORANGE'); INSERT INTO t1 VALUES (2,2,'APPLE'); INSERT INTO t1 VALUES (3,2,'APPLE'); INSERT INTO t1 VALUES (4,3,'PEAR'); SELECT DISTINCT fruit_id, fruit_name INTO @v1, @v2 FROM t1 WHERE fruit_name = 'APPLE'; SELECT @v1, @v2; @v1 @v2 2 APPLE SELECT DISTINCT fruit_id, fruit_name INTO @v3, @v4 FROM t1 GROUP BY fruit_id, fruit_name HAVING fruit_name = 'APPLE'; SELECT @v3, @v4; @v3 @v4 2 APPLE SELECT DISTINCT @v5:= fruit_id, @v6:= fruit_name INTO @v7, @v8 FROM t1 WHERE fruit_name = 'APPLE'; SELECT @v5, @v6, @v7, @v8; @v5 @v6 @v7 @v8 2 APPLE 2 APPLE SELECT DISTINCT @v5 + fruit_id, CONCAT(@v6, fruit_name) INTO @v9, @v10 FROM t1 WHERE fruit_name = 'APPLE'; SELECT @v5, @v6, @v7, @v8, @v9, @v10; @v5 @v6 @v7 @v8 @v9 @v10 2 APPLE 2 APPLE 4 APPLEAPPLE SELECT DISTINCT @v11:= @v5 + fruit_id, @v12:= CONCAT(@v6, fruit_name) INTO @v13, @v14 FROM t1 WHERE fruit_name = 'APPLE'; SELECT @v11, @v12, @v13, @v14; @v11 @v12 @v13 @v14 4 APPLEAPPLE 4 APPLEAPPLE SELECT DISTINCT @v13, @v14 INTO @v15, @v16 FROM t1 WHERE fruit_name = 'APPLE'; SELECT @v15, @v16; @v15 @v16 4 APPLEAPPLE SELECT DISTINCT 2 + 2, 'Bob' INTO @v17, @v18 FROM t1 WHERE fruit_name = 'APPLE'; SELECT @v17, @v18; @v17 @v18 4 Bob DROP TABLE IF EXISTS t2; CREATE TABLE t2 (fruit_id INT NOT NULL, fruit_name varchar(20) default NULL); SELECT DISTINCT fruit_id, fruit_name INTO OUTFILE '../../tmp/data1.tmp' FROM t1 WHERE fruit_name = 'APPLE'; LOAD DATA INFILE '../../tmp/data1.tmp' INTO TABLE t2; SELECT DISTINCT @v19:= fruit_id, @v20:= fruit_name INTO OUTFILE '../../tmp/data2.tmp' FROM t1 WHERE fruit_name = 'APPLE'; LOAD DATA INFILE '../../tmp/data2.tmp' INTO TABLE t2; SELECT @v19, @v20; @v19 @v20 2 APPLE SELECT * FROM t2; fruit_id fruit_name 2 APPLE 2 APPLE DROP TABLE t1; DROP TABLE t2; CREATE TABLE t1 (a CHAR(1)); INSERT INTO t1 VALUES('A'), (0); SELECT a FROM t1 WHERE a=0; a A 0 Warnings: Warning 1292 Truncated incorrect DOUBLE value: 'A' SELECT DISTINCT a FROM t1 WHERE a=0; a A 0 Warnings: Warning 1292 Truncated incorrect DOUBLE value: 'A' DROP TABLE t1; CREATE TABLE t1 (a DATE); INSERT INTO t1 VALUES ('1972-07-29'), ('1972-02-06'); EXPLAIN SELECT (SELECT DISTINCT a FROM t1 WHERE a = '2002-08-03'); id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL NULL No tables used 2 SUBQUERY t1 NULL ALL NULL NULL NULL NULL 2 50.00 Using where Warnings: Note 1003 /* select#1 */ select (/* select#2 */ select distinct `test`.`t1`.`a` from `test`.`t1` where (`test`.`t1`.`a` = '2002-08-03')) AS `(SELECT DISTINCT a FROM t1 WHERE a = '2002-08-03')` EXPLAIN SELECT (SELECT DISTINCT ADDDATE(a,1) FROM t1 WHERE ADDDATE(a,1) = '2002-08-03'); id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL NULL No tables used 2 SUBQUERY t1 NULL ALL NULL NULL NULL NULL 2 100.00 Using where Warnings: Note 1003 /* select#1 */ select (/* select#2 */ select distinct (`test`.`t1`.`a` + interval 1 day) from `test`.`t1` where ((`test`.`t1`.`a` + interval 1 day) = '2002-08-03')) AS `(SELECT DISTINCT ADDDATE(a,1) FROM t1 WHERE ADDDATE(a,1) = '2002-08-03')` CREATE TABLE t2 (a CHAR(5) CHARACTER SET latin1 COLLATE latin1_general_ci); INSERT INTO t2 VALUES (0xf6); INSERT INTO t2 VALUES ('oe'); SELECT COUNT(*) FROM (SELECT DISTINCT a FROM t2) dt; COUNT(*) 2 SELECT COUNT(*) FROM (SELECT DISTINCT a FROM t2 WHERE a='oe' COLLATE latin1_german2_ci) dt; COUNT(*) 2 DROP TABLE t1, t2; CREATE TABLE t1 (a INT, UNIQUE (a)); INSERT INTO t1 VALUES (4),(null),(2),(1),(null),(3); EXPLAIN SELECT DISTINCT a FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index a a 5 NULL 6 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a` from `test`.`t1` SELECT DISTINCT a FROM t1; a NULL 1 2 3 4 EXPLAIN SELECT a FROM t1 GROUP BY a; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index a a 5 NULL 6 100.00 Using index Warnings: Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` group by `test`.`t1`.`a` SELECT a FROM t1 GROUP BY a; a NULL 1 2 3 4 DROP TABLE t1; CREATE TABLE t1 (a INT, b INT); INSERT INTO t1 VALUES(1,1),(1,2),(1,3); SELECT DISTINCT a, b FROM t1; a b 1 1 1 2 1 3 SELECT DISTINCT a, a, b FROM t1; a a b 1 1 1 1 1 2 1 1 3 DROP TABLE t1; End of 5.0 tests CREATE TABLE t1(a INT, b INT, c INT, d INT, e INT, PRIMARY KEY(a,b,c,d,e), KEY(a,b,d,c) ); INSERT IGNORE INTO t1(a, b, c) VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3), (1, 2, 1), (1, 2, 2), (1, 2, 3); Warnings: Warning 1364 Field 'd' doesn't have a default value Warning 1364 Field 'e' doesn't have a default value EXPLAIN SELECT DISTINCT a, b, d, c FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL index PRIMARY,a a 16 NULL 6 100.00 Using index Warnings: Note 1003 /* select#1 */ select distinct `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`d` AS `d`,`test`.`t1`.`c` AS `c` from `test`.`t1` SELECT DISTINCT a, b, d, c FROM t1; a b d c 1 1 0 1 1 1 0 2 1 1 0 3 1 2 0 1 1 2 0 2 1 2 0 3 DROP TABLE t1; # # Bug #46159: simple query that never returns # SET @old_max_heap_table_size = @@max_heap_table_size; SET @@max_heap_table_size = 16384; SET @old_sort_buffer_size = @@sort_buffer_size; SET @@sort_buffer_size = 32804; CREATE TABLE t1(c1 int, c2 VARCHAR(20)); INSERT INTO t1 VALUES (1, '1'), (1, '1'), (2, '2'), (3, '1'), (3, '1'), (4, '4'); INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1; SELECT c1, c2, COUNT(*) FROM t1 GROUP BY c1 LIMIT 4; c1 c2 COUNT(*) 1 1 2 2 2 1 3 1 2 4 4 1 SELECT DISTINCT c2 FROM t1 GROUP BY c1 HAVING COUNT(*) > 1; c2 1 5 DROP TABLE t1; SET @@sort_buffer_size = @old_sort_buffer_size; SET @@max_heap_table_size = @old_max_heap_table_size; End of 5.1 tests # # Bug #11744875: 4082: integer lengths cause truncation with distinct concat and innodb # CREATE TABLE t1 (a INT(1), b INT(1)); INSERT INTO t1 VALUES (1111, 2222), (3333, 4444); SELECT DISTINCT CONCAT(a,b) AS c FROM t1 ORDER BY 1; c 11112222 33334444 DROP TABLE t1; # # Bug#16539979 BASIC SELECT COUNT(DISTINCT ID) IS BROKEN. # Bug#17867117 ERROR RESULT WHEN "COUNT + DISTINCT + CASE WHEN" NEED MERGE_WALK # SET @tmp_table_size_save= @@tmp_table_size; SET @@tmp_table_size= 1024; CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2),(3),(4),(5),(6),(7),(8); INSERT INTO t1 SELECT a+8 FROM t1; INSERT INTO t1 SELECT a+16 FROM t1; INSERT INTO t1 SELECT a+32 FROM t1; INSERT INTO t1 SELECT a+64 FROM t1; INSERT INTO t1 VALUE(NULL); SELECT COUNT(DISTINCT a) FROM t1; COUNT(DISTINCT a) 128 SELECT COUNT(DISTINCT (a+0)) FROM t1; COUNT(DISTINCT (a+0)) 128 DROP TABLE t1; create table tb( id int auto_increment primary key, v varchar(32)) engine=myisam charset=gbk; insert into tb(v) values("aaa"); insert into tb(v) (select v from tb); insert into tb(v) (select v from tb); insert into tb(v) (select v from tb); insert into tb(v) (select v from tb); insert into tb(v) (select v from tb); insert into tb(v) (select v from tb); update tb set v=concat(v, id); select count(distinct case when id<=64 then id end) from tb; count(distinct case when id<=64 then id end) 64 select count(distinct case when id<=63 then id end) from tb; count(distinct case when id<=63 then id end) 63 drop table tb; SET @@tmp_table_size= @tmp_table_size_save; End of 5.5 tests # # Bug#13335170 - ASSERT IN # PLAN_CHANGE_WATCHDOG::~PLAN_CHANGE_WATCHDOG() ON SELECT DISTINCT # CREATE TABLE t1 ( col_int_key int(11) NOT NULL, col_time_key time NOT NULL, col_datetime_key datetime NOT NULL, KEY col_int_key (col_int_key), KEY col_time_key (col_time_key), KEY col_datetime_key (col_datetime_key) ) ENGINE=InnoDB; INSERT INTO t1 VALUES (7,'06:17:39','2003-08-21 00:00:00'); SELECT DISTINCT col_int_key FROM t1 WHERE col_int_key IN ( 18, 6, 84, 4, 0, 2, 8, 3, 7, 9, 1 ) AND col_datetime_key BETWEEN '2001-08-04' AND '2003-06-13' ORDER BY col_time_key LIMIT 3; col_int_key DROP TABLE t1; # # BUG#13540692: WRONG NULL HANDLING WITH RIGHT JOIN + # DISTINCT OR ORDER BY # CREATE TABLE t1 ( a INT, b INT NOT NULL ); INSERT INTO t1 VALUES (1,2), (3,3); SET @save_optimizer_switch= @@optimizer_switch; SET @@SESSION.optimizer_switch="derived_merge=off"; EXPLAIN SELECT DISTINCT subselect.b FROM t1 LEFT JOIN (SELECT it_b.* FROM t1 as it_a LEFT JOIN t1 as it_b ON true) AS subselect ON t1.a = subselect.b ; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 2 100.00 Using temporary 1 PRIMARY <derived2> NULL ref <auto_key0> <auto_key0> 5 test.t1.a 2 100.00 NULL 2 DERIVED it_a NULL ALL NULL NULL NULL NULL 2 100.00 NULL 2 DERIVED it_b NULL ALL NULL NULL NULL NULL 2 100.00 Using where; Using join buffer (Block Nested Loop) Warnings: Note 1003 /* select#1 */ select distinct `subselect`.`b` AS `b` from `test`.`t1` left join (/* select#2 */ select `test`.`it_b`.`a` AS `a`,`test`.`it_b`.`b` AS `b` from `test`.`t1` `it_a` left join `test`.`t1` `it_b` on(TRUE) where 1) `subselect` on((`subselect`.`b` = `test`.`t1`.`a`)) where 1 SELECT DISTINCT subselect.b FROM t1 LEFT JOIN (SELECT it_b.* FROM t1 as it_a LEFT JOIN t1 as it_b ON true) AS subselect ON t1.a = subselect.b ; b NULL 3 SET @@SESSION.optimizer_switch= @save_optimizer_switch; DROP TABLE t1; # # BUG#13538387: WRONG RESULT ON SELECT DISTINCT + LEFT JOIN + # LIMIT + MIX OF MYISAM AND INNODB # CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (2),(3); CREATE TABLE t2 (b INT); CREATE TABLE t3 ( a INT, b INT, PRIMARY KEY (b) ); INSERT INTO t3 VALUES (2001,1), (2007,2); EXPLAIN SELECT DISTINCT t3.a AS t3_date FROM t1 LEFT JOIN t2 ON false LEFT JOIN t3 ON t2.b = t3.b LIMIT 1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t2 NULL system NULL NULL NULL NULL 0 0.00 const row not found 1 SIMPLE t3 NULL const PRIMARY NULL NULL NULL 1 100.00 Impossible ON condition 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 2 100.00 Using temporary; Distinct Warnings: Note 1003 /* select#1 */ select distinct `test`.`t3`.`a` AS `t3_date` from `test`.`t1` left join `test`.`t3` on(multiple equal(NULL, `test`.`t3`.`b`)) where 1 limit 1 SELECT DISTINCT t3.a AS t3_date FROM t1 LEFT JOIN t2 ON false LEFT JOIN t3 ON t2.b = t3.b LIMIT 1; t3_date NULL DROP TABLE t1,t2,t3; # BUG#13581713 ONLY_FULL_GROUP_BY DOES NOT BLOCK "SELECT # DISTINCT A ORDER BY B" create table t1(a int, b int, c int) engine=InnoDB; create table t2(a int, b int, c int) engine=InnoDB; insert into t2 values(); analyze table t2; Table Op Msg_type Msg_text test.t2 analyze status OK # Test when selecting from base table insert into t1 values(100,1,2),(200,1,1),(300,2,1),(400,2,2); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK select distinct b from t1 order by c; b 2 1 select distinct min(b) from t1 group by a order by min(c); min(b) 2 1 explain select distinct min(b) from t1 group by a order by min(c); id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL # 4 100.00 Using temporary; Using filesort Warnings: Note 1003 /* select#1 */ select distinct min(`test`.`t1`.`b`) AS `min(b)` from `test`.`t1` group by `test`.`t1`.`a` order by min(`test`.`t1`.`c`) Insert rows in different order: delete from t1; insert into t1 values(200,1,1),(100,1,2),(400,2,2),(300,2,1); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK And get a different order. Query is executed like this: - First, DISTINCT, using a tmp MEMORY table with a unique index, thus if two rows have the same 'b' but a different 'c', the second row is rejected, so the first value of 'c' wins (=> randomness of 'c') - Second, ORDER BY on the random 'c'. select distinct b from t1 order by c; b 1 2 Random order too (same reason): select distinct min(b) from t1 group by a order by min(c); min(b) 1 2 This query gives random order: select distinct b from t1 order by c; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct b from t1 order by b-1,b+1,c; ERROR HY000: Expression #3 of ORDER BY clause is not in SELECT list, references column 'test.t1.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct min(b) from t1 group by a order by min(c); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Not random (though Standard bans aggregates from ORDER BY): select distinct min(b) from t1 group by a order by min(b); min(b) 1 2 select distinct min(b) from t1 group by a order by -min(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT All group exprs are in select list => DISTINCT is removed => no error select distinct a, min(b) from t1 group by a order by max(b-2)-min(c*5); a min(b) 100 1 400 2 200 1 300 2 This one is standard: select distinct min(b) as z from t1 group by a order by z; z 1 2 Other queries: select distinct b from t1 where b<0 order by rand(); b select distinct b from t1 order by 45.0+3; b 1 2 select (select distinct b from t1 as S2 where b=7 order by S3.a) from t1 as S3; (select distinct b from t1 as S2 where b=7 order by S3.a) NULL NULL NULL NULL select distinct b from t1 order by abs(b); b 1 2 select distinct b as z from t1 order by abs(z); z 1 2 select distinct b from t1 order by abs(b+a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1.a' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from t1 order by z; z 1 2 select distinct abs(b) as z from t1 order by abs(b); z 1 2 select distinct abs(b) from t1 order by abs(b); abs(b) 1 2 Not ok: ABS(b)+1 is neither a SELECTed expression nor an alias to one, and mentions a column of FROM tables. select distinct abs(b) as z from t1 order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from t1 order by z+1; z 1 2 select distinct abs(b) from t1 order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from t1 order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from t1 order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1.b' which is not in SELECT list; this is incompatible with DISTINCT Two offending columns; error message needs to report only one select distinct abs(b) from t1 order by floor(10*b),floor(10*a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from t1 as S2 order by (select floor(10*S2.b) from t1 as S3 limit 1); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.S2.b' which is not in SELECT list; this is incompatible with DISTINCT Ok as S2.b in SELECT list select distinct abs(b),b from t1 as S2 order by (select floor(10*S2.b) from t1 as S3 limit 1); abs(b) b 1 1 2 2 Ok as subq does not use columns of FROM clause of ordered Q. select distinct abs(b) from t1 as S2 order by (select floor(10*S3.b) from t1 as S3 limit 1); abs(b) 1 2 Subq as alias => ok select distinct abs(b), (select floor(10*S3.b) from t1 as S3 limit 1) as subq from t1 as S2 order by subq; abs(b) subq 1 10 2 10 Bad field in left or right argument of ALL/ANY(subq): select distinct abs(b) from t1 as S2 order by floor(10*S2.b) IN (select floor(10*S3.b) from t1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from t1 as S2 order by floor(10*S2.b) > ALL(select floor(10*S3.b) from t1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from t1 as S2 order by floor(10*10) IN (select floor(10*S2.b) from t1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from t1 as S2 order by floor(10*10) > ALL(select floor(10*S2.b) from t1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.S2.b' which is not in SELECT list; this is incompatible with DISTINCT Aggregates: SELECT distinct 1 FROM t1 group by a order by count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT SELECT distinct 1 FROM t1 group by a order by count(*)-count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Test ANY_VALUE SELECT distinct 1 FROM t1 group by a order by any_value(count(*)-count(b)); 1 1 SELECT distinct 1 FROM t1 group by a order by any_value(count(*))-any_value(count(b)); 1 1 All group exprs are in select list => DISTINCT is removed => no error SELECT distinct a, min(b) FROM t1 group by a order by count(*)-count(*); a min(b) 100 1 200 1 300 2 400 2 SELECT distinct 1 FROM t1 group by a order by count(*)-count(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT aggregation in outer Q => constant in inner Q select * from t1 as t2 where t2.a in (SELECT distinct 1 FROM t1 group by a order by count(t2.a)-max(t2.a)); a b c ORDER BY expressions are in SELECT list => ok SELECT distinct 1, count(*)-count(b) FROM t1 group by a order by count(*)-count(b); 1 count(*)-count(b) 1 0 Without GROUP BY, aggregates yield a single row, no random order SELECT distinct sum(a) FROM t1 order by count(*)-count(*); sum(a) 1000 SELECT distinct sum(a) FROM t1 order by count(*)-count(b); sum(a) 1000 Verify that DISTINCT is optimized away even if the aggregate function is hidden in a subquery EXPLAIN SELECT DISTINCT MAX(b) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1003 /* select#1 */ select max(`test`.`t1`.`b`) AS `MAX(b)` from `test`.`t1` EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select (/* select#2 */ select max(`test`.`t1`.`b`) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` but if the subquery is the aggregation query, DISTINCT must stay: EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 Using temporary 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select distinct (/* select#2 */ select max((`test`.`t1`.`b` + (0 * `test`.`t2`.`a`))) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` QA's query is properly rejected: SELECT DISTINCT GP1.a AS g1 FROM t1 AS GP1 WHERE GP1.a >= 0 ORDER BY GP1.b LIMIT 8; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.GP1.b' which is not in SELECT list; this is incompatible with DISTINCT result order does change depending on chosen plan. SELECT DISTINCT GP1.a AS g1 FROM t1 AS GP1 WHERE GP1.a >= 0 ORDER BY 2+ANY_VALUE(GP1.b) LIMIT 8; g1 100 200 300 400 truncate table t1; # Test when selecting from view create view v1 as select t1.* from t1 left join t2 on 1; insert into t1 values(100,1,2),(200,1,1),(300,2,1),(400,2,2); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK select distinct b from v1 order by c; b 2 1 select distinct min(b) from v1 group by a order by min(c); min(b) 2 1 explain select distinct min(b) from v1 group by a order by min(c); id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL # 4 100.00 Using temporary; Using filesort 1 SIMPLE t2 NULL ALL NULL NULL NULL # 1 100.00 Using where; Using join buffer (Block Nested Loop) Warnings: Note 1003 /* select#1 */ select distinct min(`test`.`t1`.`b`) AS `min(b)` from `test`.`t1` left join `test`.`t2` on(1) where 1 group by `test`.`t1`.`a` order by min(`test`.`t1`.`c`) Insert rows in different order: delete from t1; insert into t1 values(200,1,1),(100,1,2),(400,2,2),(300,2,1); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK And get a different order. Query is executed like this: - First, DISTINCT, using a tmp MEMORY table with a unique index, thus if two rows have the same 'b' but a different 'c', the second row is rejected, so the first value of 'c' wins (=> randomness of 'c') - Second, ORDER BY on the random 'c'. select distinct b from v1 order by c; b 1 2 Random order too (same reason): select distinct min(b) from v1 group by a order by min(c); min(b) 1 2 This query gives random order: select distinct b from v1 order by c; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct b from v1 order by b-1,b+1,c; ERROR HY000: Expression #3 of ORDER BY clause is not in SELECT list, references column 'v1.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct min(b) from v1 group by a order by min(c); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Not random (though Standard bans aggregates from ORDER BY): select distinct min(b) from v1 group by a order by min(b); min(b) 1 2 select distinct min(b) from v1 group by a order by -min(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT All group exprs are in select list => DISTINCT is removed => no error select distinct a, min(b) from v1 group by a order by max(b-2)-min(c*5); a min(b) 100 1 400 2 200 1 300 2 This one is standard: select distinct min(b) as z from v1 group by a order by z; z 1 2 Other queries: select distinct b from v1 where b<0 order by rand(); b select distinct b from v1 order by 45.0+3; b 1 2 select (select distinct b from v1 as S2 where b=7 order by S3.a) from v1 as S3; (select distinct b from v1 as S2 where b=7 order by S3.a) NULL NULL NULL NULL select distinct b from v1 order by abs(b); b 1 2 select distinct b as z from v1 order by abs(z); z 1 2 select distinct b from v1 order by abs(b+a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.a' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from v1 order by z; z 1 2 select distinct abs(b) as z from v1 order by abs(b); z 1 2 select distinct abs(b) from v1 order by abs(b); abs(b) 1 2 Not ok: ABS(b)+1 is neither a SELECTed expression nor an alias to one, and mentions a column of FROM tables. select distinct abs(b) as z from v1 order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from v1 order by z+1; z 1 2 select distinct abs(b) from v1 order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from v1 order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT Two offending columns; error message needs to report only one select distinct abs(b) from v1 order by floor(10*b),floor(10*a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by (select floor(10*S2.b) from v1 as S3 limit 1); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT Ok as S2.b in SELECT list select distinct abs(b),b from v1 as S2 order by (select floor(10*S2.b) from v1 as S3 limit 1); abs(b) b 1 1 2 2 Ok as subq does not use columns of FROM clause of ordered Q. select distinct abs(b) from v1 as S2 order by (select floor(10*S3.b) from v1 as S3 limit 1); abs(b) 1 2 Subq as alias => ok select distinct abs(b), (select floor(10*S3.b) from v1 as S3 limit 1) as subq from v1 as S2 order by subq; abs(b) subq 1 10 2 10 Bad field in left or right argument of ALL/ANY(subq): select distinct abs(b) from v1 as S2 order by floor(10*S2.b) IN (select floor(10*S3.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by floor(10*S2.b) > ALL(select floor(10*S3.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by floor(10*10) IN (select floor(10*S2.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by floor(10*10) > ALL(select floor(10*S2.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT Aggregates: SELECT distinct 1 FROM t1 group by a order by count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT SELECT distinct 1 FROM t1 group by a order by count(*)-count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Test ANY_VALUE SELECT distinct 1 FROM t1 group by a order by any_value(count(*)-count(b)); 1 1 SELECT distinct 1 FROM t1 group by a order by any_value(count(*))-any_value(count(b)); 1 1 All group exprs are in select list => DISTINCT is removed => no error SELECT distinct a, min(b) FROM t1 group by a order by count(*)-count(*); a min(b) 100 1 200 1 300 2 400 2 SELECT distinct 1 FROM t1 group by a order by count(*)-count(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT aggregation in outer Q => constant in inner Q select * from t1 as t2 where t2.a in (SELECT distinct 1 FROM t1 group by a order by count(t2.a)-max(t2.a)); a b c ORDER BY expressions are in SELECT list => ok SELECT distinct 1, count(*)-count(b) FROM t1 group by a order by count(*)-count(b); 1 count(*)-count(b) 1 0 Without GROUP BY, aggregates yield a single row, no random order SELECT distinct sum(a) FROM t1 order by count(*)-count(*); sum(a) 1000 SELECT distinct sum(a) FROM t1 order by count(*)-count(b); sum(a) 1000 Verify that DISTINCT is optimized away even if the aggregate function is hidden in a subquery EXPLAIN SELECT DISTINCT MAX(b) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1003 /* select#1 */ select max(`test`.`t1`.`b`) AS `MAX(b)` from `test`.`t1` EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select (/* select#2 */ select max(`test`.`t1`.`b`) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` but if the subquery is the aggregation query, DISTINCT must stay: EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 Using temporary 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select distinct (/* select#2 */ select max((`test`.`t1`.`b` + (0 * `test`.`t2`.`a`))) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` QA's query is properly rejected: SELECT DISTINCT GP1.a AS g1 FROM v1 AS GP1 WHERE GP1.a >= 0 ORDER BY GP1.b LIMIT 8; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'GP1.b' which is not in SELECT list; this is incompatible with DISTINCT result order does change depending on chosen plan. SELECT DISTINCT GP1.a AS g1 FROM v1 AS GP1 WHERE GP1.a >= 0 ORDER BY 2+ANY_VALUE(GP1.b) LIMIT 8; g1 100 200 300 400 truncate table t1; drop view v1; # Test when selecting from view, again create view v1 as select t1.a*2 as a, t1.b*2 as b, t1.c*2 as c from t1; insert into t1 values(100,1,2),(200,1,1),(300,2,1),(400,2,2); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK select distinct b from v1 order by c; b 4 2 select distinct min(b) from v1 group by a order by min(c); min(b) 4 2 explain select distinct min(b) from v1 group by a order by min(c); id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL # 4 100.00 Using temporary; Using filesort Warnings: Note 1003 /* select#1 */ select distinct min((`test`.`t1`.`b` * 2)) AS `min(b)` from `test`.`t1` group by (`test`.`t1`.`a` * 2) order by min((`test`.`t1`.`c` * 2)) Insert rows in different order: delete from t1; insert into t1 values(200,1,1),(100,1,2),(400,2,2),(300,2,1); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK And get a different order. Query is executed like this: - First, DISTINCT, using a tmp MEMORY table with a unique index, thus if two rows have the same 'b' but a different 'c', the second row is rejected, so the first value of 'c' wins (=> randomness of 'c') - Second, ORDER BY on the random 'c'. select distinct b from v1 order by c; b 2 4 Random order too (same reason): select distinct min(b) from v1 group by a order by min(c); min(b) 2 4 This query gives random order: select distinct b from v1 order by c; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct b from v1 order by b-1,b+1,c; ERROR HY000: Expression #3 of ORDER BY clause is not in SELECT list, references column 'v1.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct min(b) from v1 group by a order by min(c); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Not random (though Standard bans aggregates from ORDER BY): select distinct min(b) from v1 group by a order by min(b); min(b) 2 4 select distinct min(b) from v1 group by a order by -min(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT All group exprs are in select list => DISTINCT is removed => no error select distinct a, min(b) from v1 group by a order by max(b-2)-min(c*5); a min(b) 200 2 800 4 400 2 600 4 This one is standard: select distinct min(b) as z from v1 group by a order by z; z 2 4 Other queries: select distinct b from v1 where b<0 order by rand(); b select distinct b from v1 order by 45.0+3; b 2 4 select (select distinct b from v1 as S2 where b=7 order by S3.a) from v1 as S3; (select distinct b from v1 as S2 where b=7 order by S3.a) NULL NULL NULL NULL select distinct b from v1 order by abs(b); b 2 4 select distinct b as z from v1 order by abs(z); z 2 4 select distinct b from v1 order by abs(b+a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.a' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from v1 order by z; z 2 4 select distinct abs(b) as z from v1 order by abs(b); z 2 4 select distinct abs(b) from v1 order by abs(b); abs(b) 2 4 Not ok: ABS(b)+1 is neither a SELECTed expression nor an alias to one, and mentions a column of FROM tables. select distinct abs(b) as z from v1 order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from v1 order by z+1; z 2 4 select distinct abs(b) from v1 order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from v1 order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT Two offending columns; error message needs to report only one select distinct abs(b) from v1 order by floor(10*b),floor(10*a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'v1.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by (select floor(10*S2.b) from v1 as S3 limit 1); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT Ok as S2.b in SELECT list select distinct abs(b),b from v1 as S2 order by (select floor(10*S2.b) from v1 as S3 limit 1); abs(b) b 2 2 4 4 Ok as subq does not use columns of FROM clause of ordered Q. select distinct abs(b) from v1 as S2 order by (select floor(10*S3.b) from v1 as S3 limit 1); abs(b) 2 4 Subq as alias => ok select distinct abs(b), (select floor(10*S3.b) from v1 as S3 limit 1) as subq from v1 as S2 order by subq; abs(b) subq 2 20 4 20 Bad field in left or right argument of ALL/ANY(subq): select distinct abs(b) from v1 as S2 order by floor(10*S2.b) IN (select floor(10*S3.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by floor(10*S2.b) > ALL(select floor(10*S3.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by floor(10*10) IN (select floor(10*S2.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from v1 as S2 order by floor(10*10) > ALL(select floor(10*S2.b) from v1 as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT Aggregates: SELECT distinct 1 FROM t1 group by a order by count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT SELECT distinct 1 FROM t1 group by a order by count(*)-count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Test ANY_VALUE SELECT distinct 1 FROM t1 group by a order by any_value(count(*)-count(b)); 1 1 SELECT distinct 1 FROM t1 group by a order by any_value(count(*))-any_value(count(b)); 1 1 All group exprs are in select list => DISTINCT is removed => no error SELECT distinct a, min(b) FROM t1 group by a order by count(*)-count(*); a min(b) 100 1 200 1 300 2 400 2 SELECT distinct 1 FROM t1 group by a order by count(*)-count(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT aggregation in outer Q => constant in inner Q select * from t1 as t2 where t2.a in (SELECT distinct 1 FROM t1 group by a order by count(t2.a)-max(t2.a)); a b c ORDER BY expressions are in SELECT list => ok SELECT distinct 1, count(*)-count(b) FROM t1 group by a order by count(*)-count(b); 1 count(*)-count(b) 1 0 Without GROUP BY, aggregates yield a single row, no random order SELECT distinct sum(a) FROM t1 order by count(*)-count(*); sum(a) 1000 SELECT distinct sum(a) FROM t1 order by count(*)-count(b); sum(a) 1000 Verify that DISTINCT is optimized away even if the aggregate function is hidden in a subquery EXPLAIN SELECT DISTINCT MAX(b) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1003 /* select#1 */ select max(`test`.`t1`.`b`) AS `MAX(b)` from `test`.`t1` EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select (/* select#2 */ select max(`test`.`t1`.`b`) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` but if the subquery is the aggregation query, DISTINCT must stay: EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 Using temporary 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select distinct (/* select#2 */ select max((`test`.`t1`.`b` + (0 * `test`.`t2`.`a`))) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` QA's query is properly rejected: SELECT DISTINCT GP1.a AS g1 FROM v1 AS GP1 WHERE GP1.a >= 0 ORDER BY GP1.b LIMIT 8; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'GP1.b' which is not in SELECT list; this is incompatible with DISTINCT result order does change depending on chosen plan. SELECT DISTINCT GP1.a AS g1 FROM v1 AS GP1 WHERE GP1.a >= 0 ORDER BY 2+ANY_VALUE(GP1.b) LIMIT 8; g1 200 400 600 800 truncate table t1; drop view v1; # Test when selecting from derived table insert into t1 values(100,1,2),(200,1,1),(300,2,1),(400,2,2); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by c; b 2 1 select distinct min(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by min(c); min(b) 2 1 explain select distinct min(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by min(c); id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL # 4 100.00 Using temporary; Using filesort 1 SIMPLE t2 NULL ALL NULL NULL NULL # 1 100.00 Using where; Using join buffer (Block Nested Loop) Warnings: Note 1003 /* select#1 */ select distinct min(`test`.`t1`.`b`) AS `min(b)` from `test`.`t1` left join `test`.`t2` on(1) where 1 group by `test`.`t1`.`a` order by min(`test`.`t1`.`c`) Insert rows in different order: delete from t1; insert into t1 values(200,1,1),(100,1,2),(400,2,2),(300,2,1); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK And get a different order. Query is executed like this: - First, DISTINCT, using a tmp MEMORY table with a unique index, thus if two rows have the same 'b' but a different 'c', the second row is rejected, so the first value of 'c' wins (=> randomness of 'c') - Second, ORDER BY on the random 'c'. select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by c; b 1 2 Random order too (same reason): select distinct min(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by min(c); min(b) 1 2 This query gives random order: select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by c; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'derived.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by b-1,b+1,c; ERROR HY000: Expression #3 of ORDER BY clause is not in SELECT list, references column 'derived.c' which is not in SELECT list; this is incompatible with DISTINCT and this one too: select distinct min(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by min(c); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Not random (though Standard bans aggregates from ORDER BY): select distinct min(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by min(b); min(b) 1 2 select distinct min(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by -min(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT All group exprs are in select list => DISTINCT is removed => no error select distinct a, min(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by max(b-2)-min(c*5); a min(b) 100 1 400 2 200 1 300 2 This one is standard: select distinct min(b) as z from (SELECT t1.* FROM t1 left join t2 on 1) AS derived group by a order by z; z 1 2 Other queries: select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived where b<0 order by rand(); b select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by 45.0+3; b 1 2 select (select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) as S2 where b=7 order by S3.a) from (SELECT t1.* FROM t1 left join t2 on 1) as S3; (select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) as S2 where b=7 order by S3.a) NULL NULL NULL NULL select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by abs(b); b 1 2 select distinct b as z from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by abs(z); z 1 2 select distinct b from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by abs(b+a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'derived.a' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by z; z 1 2 select distinct abs(b) as z from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by abs(b); z 1 2 select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by abs(b); abs(b) 1 2 Not ok: ABS(b)+1 is neither a SELECTed expression nor an alias to one, and mentions a column of FROM tables. select distinct abs(b) as z from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'derived.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by z+1; z 1 2 select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by abs(b)+1; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'derived.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) as z from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'derived.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by floor(10*b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'derived.b' which is not in SELECT list; this is incompatible with DISTINCT Two offending columns; error message needs to report only one select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) AS derived order by floor(10*b),floor(10*a); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'derived.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by (select floor(10*S2.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3 limit 1); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT Ok as S2.b in SELECT list select distinct abs(b),b from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by (select floor(10*S2.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3 limit 1); abs(b) b 1 1 2 2 Ok as subq does not use columns of FROM clause of ordered Q. select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by (select floor(10*S3.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3 limit 1); abs(b) 1 2 Subq as alias => ok select distinct abs(b), (select floor(10*S3.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3 limit 1) as subq from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by subq; abs(b) subq 1 10 2 10 Bad field in left or right argument of ALL/ANY(subq): select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by floor(10*S2.b) IN (select floor(10*S3.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by floor(10*S2.b) > ALL(select floor(10*S3.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by floor(10*10) IN (select floor(10*S2.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct abs(b) from (SELECT t1.* FROM t1 left join t2 on 1) as S2 order by floor(10*10) > ALL(select floor(10*S2.b) from (SELECT t1.* FROM t1 left join t2 on 1) as S3); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'S2.b' which is not in SELECT list; this is incompatible with DISTINCT Aggregates: SELECT distinct 1 FROM t1 group by a order by count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT SELECT distinct 1 FROM t1 group by a order by count(*)-count(*); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT Test ANY_VALUE SELECT distinct 1 FROM t1 group by a order by any_value(count(*)-count(b)); 1 1 SELECT distinct 1 FROM t1 group by a order by any_value(count(*))-any_value(count(b)); 1 1 All group exprs are in select list => DISTINCT is removed => no error SELECT distinct a, min(b) FROM t1 group by a order by count(*)-count(*); a min(b) 100 1 200 1 300 2 400 2 SELECT distinct 1 FROM t1 group by a order by count(*)-count(b); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, contains aggregate function; this is incompatible with DISTINCT aggregation in outer Q => constant in inner Q select * from t1 as t2 where t2.a in (SELECT distinct 1 FROM t1 group by a order by count(t2.a)-max(t2.a)); a b c ORDER BY expressions are in SELECT list => ok SELECT distinct 1, count(*)-count(b) FROM t1 group by a order by count(*)-count(b); 1 count(*)-count(b) 1 0 Without GROUP BY, aggregates yield a single row, no random order SELECT distinct sum(a) FROM t1 order by count(*)-count(*); sum(a) 1000 SELECT distinct sum(a) FROM t1 order by count(*)-count(b); sum(a) 1000 Verify that DISTINCT is optimized away even if the aggregate function is hidden in a subquery EXPLAIN SELECT DISTINCT MAX(b) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1003 /* select#1 */ select max(`test`.`t1`.`b`) AS `MAX(b)` from `test`.`t1` EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 NULL 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select (/* select#2 */ select max(`test`.`t1`.`b`) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` but if the subquery is the aggregation query, DISTINCT must stay: EXPLAIN SELECT DISTINCT (SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1) FROM t1; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 4 100.00 Using temporary 2 DEPENDENT SUBQUERY t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL Warnings: Note 1276 Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1 Note 1003 /* select#1 */ select distinct (/* select#2 */ select max((`test`.`t1`.`b` + (0 * `test`.`t2`.`a`))) from `test`.`t1` `t2` limit 1) AS `(SELECT MAX(t1.b+0*t2.a) FROM t1 AS t2 LIMIT 1)` from `test`.`t1` QA's query is properly rejected: SELECT DISTINCT GP1.a AS g1 FROM (SELECT t1.* FROM t1 left join t2 on 1) AS GP1 WHERE GP1.a >= 0 ORDER BY GP1.b LIMIT 8; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'GP1.b' which is not in SELECT list; this is incompatible with DISTINCT result order does change depending on chosen plan. SELECT DISTINCT GP1.a AS g1 FROM (SELECT t1.* FROM t1 left join t2 on 1) AS GP1 WHERE GP1.a >= 0 ORDER BY 2+ANY_VALUE(GP1.b) LIMIT 8; g1 100 200 300 400 truncate table t1; select distinct t1_outer.a from t1 t1_outer order by t1_outer.b; ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1_outer.b' which is not in SELECT list; this is incompatible with DISTINCT select distinct t1_outer.a from t1 t1_outer order by (select max(t1_outer.b+t1_inner.b) from t1 t1_inner); ERROR HY000: Expression #1 of ORDER BY clause is not in SELECT list, references column 'test.t1_outer.b' which is not in SELECT list; this is incompatible with DISTINCT select (select distinct 1 from t1 t1_inner group by t1_inner.a order by max(t1_outer.b)) from t1 t1_outer; (select distinct 1 from t1 t1_inner group by t1_inner.a order by max(t1_outer.b)) NULL drop table t1, t2; # # Bug#22686994 REGRESSION FOR A GROUPING QUERY WITH DISTINCT # CREATE TABLE t1 (a INTEGER, b INTEGER); INSERT INTO t1 VALUES (1,3), (2,4), (1,5), (1,3), (2,1), (1,5), (1,7), (3,1), (3,2), (3,1), (2,4); SELECT DISTINCT (COUNT(DISTINCT b) + 1) AS c FROM t1 GROUP BY a; c 4 3 DROP TABLE t1; # End of test for Bug#22686994