drop table if exists t1,t2,t3; SELECT 1 FROM (SELECT 1) as a GROUP BY SUM(1); ERROR HY000: Invalid use of group function CREATE TABLE t1 ( spID int(10) unsigned, userID int(10) unsigned, score smallint(5) unsigned, lsg char(40), date date ); INSERT INTO t1 VALUES (1,1,1,'','0000-00-00'); INSERT INTO t1 VALUES (2,2,2,'','0000-00-00'); INSERT INTO t1 VALUES (2,1,1,'','0000-00-00'); INSERT INTO t1 VALUES (3,3,3,'','0000-00-00'); CREATE TABLE t2 ( userID int(10) unsigned NOT NULL auto_increment, niName char(15), passwd char(8), mail char(50), isAukt enum('N','Y') DEFAULT 'N', vName char(30), nName char(40), adr char(60), plz char(5), ort char(35), land char(20), PRIMARY KEY (userID) ); INSERT INTO t2 VALUES (1,'name','pass','mail','Y','v','n','adr','1','1','1'); INSERT INTO t2 VALUES (2,'name','pass','mail','Y','v','n','adr','1','1','1'); INSERT INTO t2 VALUES (3,'name','pass','mail','Y','v','n','adr','1','1','1'); INSERT INTO t2 VALUES (4,'name','pass','mail','Y','v','n','adr','1','1','1'); INSERT INTO t2 VALUES (5,'name','pass','mail','Y','v','n','adr','1','1','1'); SELECT t2.userid, MIN(t1.score) FROM t1, t2 WHERE t1.userID=t2.userID GROUP BY t2.userid; userid MIN(t1.score) 1 1 2 2 3 3 SELECT t2.userid, MIN(t1.score) FROM t1, t2 WHERE t1.userID=t2.userID GROUP BY t2.userid ORDER BY NULL; userid MIN(t1.score) 1 1 2 2 3 3 SELECT t2.userid, MIN(t1.score) FROM t1, t2 WHERE t1.userID=t2.userID AND t1.spID=2 GROUP BY t2.userid; userid MIN(t1.score) 1 1 2 2 SELECT t2.userid, MIN(t1.score+0.0) FROM t1, t2 WHERE t1.userID=t2.userID AND t1.spID=2 GROUP BY t2.userid; userid MIN(t1.score+0.0) 1 1.0 2 2.0 SELECT t2.userid, MIN(t1.score+0.0) FROM t1, t2 WHERE t1.userID=t2.userID AND t1.spID=2 GROUP BY t2.userid ORDER BY NULL; userid MIN(t1.score+0.0) 2 2.0 1 1.0 EXPLAIN SELECT t2.userid, MIN(t1.score+0.0) FROM t1, t2 WHERE t1.userID=t2.userID AND t1.spID=2 GROUP BY t2.userid ORDER BY NULL; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where; Using temporary 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.userID 1 Using index drop table t1,t2; CREATE TABLE t1 ( PID int(10) unsigned NOT NULL auto_increment, payDate date DEFAULT '0000-00-00' NOT NULL, recDate datetime DEFAULT '0000-00-00 00:00:00' NOT NULL, URID int(10) unsigned DEFAULT '0' NOT NULL, CRID int(10) unsigned DEFAULT '0' NOT NULL, amount int(10) unsigned DEFAULT '0' NOT NULL, operator int(10) unsigned, method enum('unknown','cash','dealer','check','card','lazy','delayed','test') DEFAULT 'unknown' NOT NULL, DIID int(10) unsigned, reason char(1) binary DEFAULT '' NOT NULL, code_id int(10) unsigned, qty mediumint(8) unsigned DEFAULT '0' NOT NULL, PRIMARY KEY (PID), KEY URID (URID), KEY reason (reason), KEY method (method), KEY payDate (payDate) ); INSERT INTO t1 VALUES (1,'1970-01-01','1997-10-17 00:00:00',2529,1,21000,11886,'check',0,'F',16200,6); SELECT COUNT(P.URID),SUM(P.amount),P.method, MIN(PP.recdate+0) > 19980501000000 AS IsNew FROM t1 AS P JOIN t1 as PP WHERE P.URID = PP.URID GROUP BY method,IsNew; ERROR 42000: Can't group on 'IsNew' drop table t1; CREATE TABLE t1 ( cid mediumint(9) NOT NULL auto_increment, firstname varchar(32) DEFAULT '' NOT NULL, surname varchar(32) DEFAULT '' NOT NULL, PRIMARY KEY (cid) ); INSERT INTO t1 VALUES (1,'That','Guy'); INSERT INTO t1 VALUES (2,'Another','Gent'); CREATE TABLE t2 ( call_id mediumint(8) NOT NULL auto_increment, contact_id mediumint(8) DEFAULT '0' NOT NULL, PRIMARY KEY (call_id), KEY contact_id (contact_id) ); lock tables t1 read,t2 write; INSERT INTO t2 VALUES (10,2); INSERT INTO t2 VALUES (18,2); INSERT INTO t2 VALUES (62,2); INSERT INTO t2 VALUES (91,2); INSERT INTO t2 VALUES (92,2); SELECT cid, CONCAT(firstname, ' ', surname), COUNT(call_id) FROM t1 LEFT JOIN t2 ON cid=contact_id WHERE firstname like '%foo%' GROUP BY cid; cid CONCAT(firstname, ' ', surname) COUNT(call_id) SELECT cid, CONCAT(firstname, ' ', surname), COUNT(call_id) FROM t1 LEFT JOIN t2 ON cid=contact_id WHERE firstname like '%foo%' GROUP BY cid ORDER BY NULL; cid CONCAT(firstname, ' ', surname) COUNT(call_id) SELECT HIGH_PRIORITY cid, CONCAT(firstname, ' ', surname), COUNT(call_id) FROM t1 LEFT JOIN t2 ON cid=contact_id WHERE firstname like '%foo%' GROUP BY cid ORDER BY surname, firstname; cid CONCAT(firstname, ' ', surname) COUNT(call_id) drop table t1,t2; unlock tables; CREATE TABLE t1 ( bug_id mediumint(9) NOT NULL auto_increment, groupset bigint(20) DEFAULT '0' NOT NULL, assigned_to mediumint(9) DEFAULT '0' NOT NULL, bug_file_loc text, bug_severity enum('blocker','critical','major','normal','minor','trivial','enhancement') DEFAULT 'blocker' NOT NULL, bug_status enum('','NEW','ASSIGNED','REOPENED','RESOLVED','VERIFIED','CLOSED') DEFAULT 'NEW' NOT NULL, creation_ts datetime DEFAULT '0000-00-00 00:00:00' NOT NULL, delta_ts timestamp(14), short_desc mediumtext, long_desc mediumtext, op_sys enum('All','Windows 3.1','Windows 95','Windows 98','Windows NT','Windows 2000','Linux','other') DEFAULT 'All' NOT NULL, priority enum('P1','P2','P3','P4','P5') DEFAULT 'P1' NOT NULL, product varchar(64) DEFAULT '' NOT NULL, rep_platform enum('All','PC','VTD-8','Other'), reporter mediumint(9) DEFAULT '0' NOT NULL, version varchar(16) DEFAULT '' NOT NULL, component varchar(50) DEFAULT '' NOT NULL, resolution enum('','FIXED','INVALID','WONTFIX','LATER','REMIND','DUPLICATE','WORKSFORME') DEFAULT '' NOT NULL, target_milestone varchar(20) DEFAULT '' NOT NULL, qa_contact mediumint(9) DEFAULT '0' NOT NULL, status_whiteboard mediumtext NOT NULL, votes mediumint(9) DEFAULT '0' NOT NULL, PRIMARY KEY (bug_id), KEY assigned_to (assigned_to), KEY creation_ts (creation_ts), KEY delta_ts (delta_ts), KEY bug_severity (bug_severity), KEY bug_status (bug_status), KEY op_sys (op_sys), KEY priority (priority), KEY product (product), KEY reporter (reporter), KEY version (version), KEY component (component), KEY resolution (resolution), KEY target_milestone (target_milestone), KEY qa_contact (qa_contact), KEY votes (votes) ); INSERT INTO t1 VALUES (1,0,0,'','normal','','2000-02-10 09:25:12',20000321114747,'','','Linux','P1','TestProduct','PC',3,'other','TestComponent','','M1',0,'',0); INSERT INTO t1 VALUES (9,0,0,'','enhancement','','2000-03-10 11:49:36',20000321114747,'','','All','P5','AAAAA','PC',3,'2.00 CD - Pre','BBBBBBBBBBBBB - conversion','','',0,'',0); INSERT INTO t1 VALUES (10,0,0,'','enhancement','','2000-03-10 18:10:16',20000321114747,'','','All','P4','AAAAA','PC',3,'2.00 CD - Pre','BBBBBBBBBBBBB - conversion','','',0,'',0); INSERT INTO t1 VALUES (7,0,0,'','critical','','2000-03-09 10:50:21',20000321114747,'','','All','P1','AAAAA','PC',3,'2.00 CD - Pre','BBBBBBBBBBBBB - generic','','',0,'',0); INSERT INTO t1 VALUES (6,0,0,'','normal','','2000-03-09 10:42:44',20000321114747,'','','All','P2','AAAAA','PC',3,'2.00 CD - Pre','kkkkkkkkkkk lllllllllll','','',0,'',0); INSERT INTO t1 VALUES (8,0,0,'','major','','2000-03-09 11:32:14',20000321114747,'','','All','P3','AAAAA','PC',3,'2.00 CD - Pre','kkkkkkkkkkk lllllllllll','','',0,'',0); INSERT INTO t1 VALUES (5,0,0,'','enhancement','','2000-03-09 10:38:59',20000321114747,'','','All','P5','CCC/CCCCCC','PC',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (4,0,0,'','normal','','2000-03-08 18:32:14',20000321114747,'','','other','P2','TestProduct','Other',3,'other','TestComponent2','','',0,'',0); INSERT INTO t1 VALUES (3,0,0,'','normal','','2000-03-08 18:30:52',20000321114747,'','','other','P2','TestProduct','Other',3,'other','TestComponent','','',0,'',0); INSERT INTO t1 VALUES (2,0,0,'','enhancement','','2000-03-08 18:24:51',20000321114747,'','','All','P2','TestProduct','Other',4,'other','TestComponent2','','',0,'',0); INSERT INTO t1 VALUES (11,0,0,'','blocker','','2000-03-13 09:43:41',20000321114747,'','','All','P2','CCC/CCCCCC','PC',5,'7.00','DDDDDDDDD','','',0,'',0); INSERT INTO t1 VALUES (12,0,0,'','normal','','2000-03-13 16:14:31',20000321114747,'','','All','P2','AAAAA','PC',3,'2.00 CD - Pre','kkkkkkkkkkk lllllllllll','','',0,'',0); INSERT INTO t1 VALUES (13,0,0,'','normal','','2000-03-15 16:20:44',20000321114747,'','','other','P2','TestProduct','Other',3,'other','TestComponent','','',0,'',0); INSERT INTO t1 VALUES (14,0,0,'','blocker','','2000-03-15 18:13:47',20000321114747,'','','All','P1','AAAAA','PC',3,'2.00 CD - Pre','BBBBBBBBBBBBB - generic','','',0,'',0); INSERT INTO t1 VALUES (15,0,0,'','minor','','2000-03-16 18:03:28',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','DDDDDDDDD','','',0,'',0); INSERT INTO t1 VALUES (16,0,0,'','normal','','2000-03-16 18:33:41',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (17,0,0,'','normal','','2000-03-16 18:34:18',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (18,0,0,'','normal','','2000-03-16 18:34:56',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (19,0,0,'','enhancement','','2000-03-16 18:35:34',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (20,0,0,'','enhancement','','2000-03-16 18:36:23',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (21,0,0,'','enhancement','','2000-03-16 18:37:23',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (22,0,0,'','enhancement','','2000-03-16 18:38:16',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','Administration','','',0,'',0); INSERT INTO t1 VALUES (23,0,0,'','normal','','2000-03-16 18:58:12',20000321114747,'','','All','P2','CCC/CCCCCC','Other',5,'7.00','DDDDDDDDD','','',0,'',0); INSERT INTO t1 VALUES (24,0,0,'','normal','','2000-03-17 11:08:10',20000321114747,'','','All','P2','AAAAAAAA-AAA','PC',3,'2.8','Web Interface','','',0,'',0); INSERT INTO t1 VALUES (25,0,0,'','normal','','2000-03-17 11:10:45',20000321114747,'','','All','P2','AAAAAAAA-AAA','PC',3,'2.8','Web Interface','','',0,'',0); INSERT INTO t1 VALUES (26,0,0,'','normal','','2000-03-17 11:15:47',20000321114747,'','','All','P2','AAAAAAAA-AAA','PC',3,'2.8','Web Interface','','',0,'',0); INSERT INTO t1 VALUES (27,0,0,'','normal','','2000-03-17 17:45:41',20000321114747,'','','All','P2','CCC/CCCCCC','PC',5,'7.00','DDDDDDDDD','','',0,'',0); INSERT INTO t1 VALUES (28,0,0,'','normal','','2000-03-20 09:51:45',20000321114747,'','','Windows NT','P2','TestProduct','PC',8,'other','TestComponent','','',0,'',0); INSERT INTO t1 VALUES (29,0,0,'','normal','','2000-03-20 11:15:09',20000321114747,'','','All','P5','AAAAAAAA-AAA','PC',3,'2.8','Web Interface','','',0,'',0); CREATE TABLE t2 ( value tinytext, program varchar(64), initialowner tinytext NOT NULL, initialqacontact tinytext NOT NULL, description mediumtext NOT NULL ); INSERT INTO t2 VALUES ('TestComponent','TestProduct','id0001','',''); INSERT INTO t2 VALUES ('BBBBBBBBBBBBB - conversion','AAAAA','id0001','',''); INSERT INTO t2 VALUES ('BBBBBBBBBBBBB - generic','AAAAA','id0001','',''); INSERT INTO t2 VALUES ('TestComponent2','TestProduct','id0001','',''); INSERT INTO t2 VALUES ('BBBBBBBBBBBBB - eeeeeeeee','AAAAA','id0001','',''); INSERT INTO t2 VALUES ('kkkkkkkkkkk lllllllllll','AAAAA','id0001','',''); INSERT INTO t2 VALUES ('Test Procedures','AAAAA','id0001','',''); INSERT INTO t2 VALUES ('Documentation','AAAAA','id0003','',''); INSERT INTO t2 VALUES ('DDDDDDDDD','CCC/CCCCCC','id0002','',''); INSERT INTO t2 VALUES ('Eeeeeeee Lite','CCC/CCCCCC','id0002','',''); INSERT INTO t2 VALUES ('Eeeeeeee Full','CCC/CCCCCC','id0002','',''); INSERT INTO t2 VALUES ('Administration','CCC/CCCCCC','id0002','',''); INSERT INTO t2 VALUES ('Distribution','CCC/CCCCCC','id0002','',''); INSERT INTO t2 VALUES ('Setup','CCC/CCCCCC','id0002','',''); INSERT INTO t2 VALUES ('Unspecified','CCC/CCCCCC','id0002','',''); INSERT INTO t2 VALUES ('Web Interface','AAAAAAAA-AAA','id0001','',''); INSERT INTO t2 VALUES ('Host communication','AAAAA','id0001','',''); select value,description,bug_id from t2 left join t1 on t2.program=t1.product and t2.value=t1.component where program="AAAAA"; value description bug_id BBBBBBBBBBBBB - conversion 9 BBBBBBBBBBBBB - conversion 10 BBBBBBBBBBBBB - generic 7 BBBBBBBBBBBBB - generic 14 BBBBBBBBBBBBB - eeeeeeeee NULL kkkkkkkkkkk lllllllllll 6 kkkkkkkkkkk lllllllllll 8 kkkkkkkkkkk lllllllllll 12 Test Procedures NULL Documentation NULL Host communication NULL select value,description,COUNT(bug_id) from t2 left join t1 on t2.program=t1.product and t2.value=t1.component where program="AAAAA" group by value; value description COUNT(bug_id) BBBBBBBBBBBBB - conversion 2 BBBBBBBBBBBBB - eeeeeeeee 0 BBBBBBBBBBBBB - generic 2 Documentation 0 Host communication 0 kkkkkkkkkkk lllllllllll 3 Test Procedures 0 select value,description,COUNT(bug_id) from t2 left join t1 on t2.program=t1.product and t2.value=t1.component where program="AAAAA" group by value having COUNT(bug_id) IN (0,2); value description COUNT(bug_id) BBBBBBBBBBBBB - conversion 2 BBBBBBBBBBBBB - eeeeeeeee 0 BBBBBBBBBBBBB - generic 2 Documentation 0 Host communication 0 Test Procedures 0 drop table t1,t2; create table t1 (foo int); insert into t1 values (1); select 1+1, "a",count(*) from t1 where foo in (2); 1+1 a count(*) 2 a 0 insert into t1 values (1); select 1+1,"a",count(*) from t1 where foo in (2); 1+1 a count(*) 2 a 0 drop table t1; CREATE TABLE t1 ( spID int(10) unsigned, userID int(10) unsigned, score smallint(5) unsigned, key (spid), key (score) ); INSERT INTO t1 VALUES (1,1,1),(2,2,2),(2,1,1),(3,3,3),(4,3,3),(5,3,3),(6,3,3),(7,3,3); explain select userid,count(*) from t1 group by userid desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 8 Using temporary; Using filesort explain select userid,count(*) from t1 group by userid desc order by null; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 8 Using temporary select userid,count(*) from t1 group by userid desc; userid count(*) 3 5 2 1 1 2 select userid,count(*) from t1 group by userid desc having (count(*)+1) IN (4,3); userid count(*) 1 2 select userid,count(*) from t1 group by userid desc having 3 IN (1,COUNT(*)); userid count(*) explain select spid,count(*) from t1 where spid between 1 and 2 group by spid desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range spID spID 5 NULL 3 Using where; Using index explain select spid,count(*) from t1 where spid between 1 and 2 group by spid; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range spID spID 5 NULL 3 Using where; Using index explain select spid,count(*) from t1 where spid between 1 and 2 group by spid order by null; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range spID spID 5 NULL 3 Using where; Using index select spid,count(*) from t1 where spid between 1 and 2 group by spid; spid count(*) 1 1 2 2 select spid,count(*) from t1 where spid between 1 and 2 group by spid desc; spid count(*) 2 2 1 1 explain extended select sql_big_result spid,sum(userid) from t1 group by spid desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 8 Using filesort Warnings: Note 1003 select sql_big_result test.t1.spID AS `spid`,sum(test.t1.userID) AS `sum(userid)` from test.t1 group by test.t1.spID desc explain select sql_big_result spid,sum(userid) from t1 group by spid desc order by null; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 8 Using filesort select sql_big_result spid,sum(userid) from t1 group by spid desc; spid sum(userid) 7 3 6 3 5 3 4 3 3 3 2 3 1 1 explain select sql_big_result score,count(*) from t1 group by score desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL score 3 NULL 8 Using index explain select sql_big_result score,count(*) from t1 group by score desc order by null; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL score 3 NULL 8 Using index select sql_big_result score,count(*) from t1 group by score desc; score count(*) 3 5 2 1 1 2 drop table t1; create table t1 (a date default null, b date default null); insert t1 values ('1999-10-01','2000-01-10'), ('1997-01-01','1998-10-01'); select a,min(b) c,count(distinct rand()) from t1 group by a having c<a + interval 1 day; a c count(distinct rand()) drop table t1; CREATE TABLE t1 (a char(1)); INSERT INTO t1 VALUES ('A'),('B'),('A'),('B'),('A'),('B'),(NULL),('a'),('b'),(NULL),('A'),('B'),(NULL); SELECT a FROM t1 GROUP BY a; a NULL A B SELECT a,count(*) FROM t1 GROUP BY a; a count(*) NULL 3 A 5 B 5 SELECT a FROM t1 GROUP BY binary a; a NULL A B a b SELECT a,count(*) FROM t1 GROUP BY binary a; a count(*) NULL 3 A 4 B 4 a 1 b 1 SELECT binary a FROM t1 GROUP BY 1; binary a NULL A B a b SELECT binary a,count(*) FROM t1 GROUP BY 1; binary a count(*) NULL 3 A 4 B 4 a 1 b 1 SET SQL_BIG_TABLES=1; SELECT a FROM t1 GROUP BY a; a NULL A B SELECT a,count(*) FROM t1 GROUP BY a; a count(*) NULL 3 A 5 B 5 SELECT a FROM t1 GROUP BY binary a; a NULL A B a b SELECT a,count(*) FROM t1 GROUP BY binary a; a count(*) NULL 3 A 4 B 4 a 1 b 1 SELECT binary a FROM t1 GROUP BY 1; binary a NULL A B a b SELECT binary a,count(*) FROM t1 GROUP BY 1; binary a count(*) NULL 3 A 4 B 4 a 1 b 1 SET SQL_BIG_TABLES=0; drop table t1; CREATE TABLE t1 ( `a` char(193) default NULL, `b` char(63) default NULL ); INSERT INTO t1 VALUES ('abc','def'),('hij','klm'); SELECT CONCAT(a, b) FROM t1 GROUP BY 1; CONCAT(a, b) abcdef hijklm SELECT CONCAT(a, b),count(*) FROM t1 GROUP BY 1; CONCAT(a, b) count(*) abcdef 1 hijklm 1 SELECT CONCAT(a, b),count(distinct a) FROM t1 GROUP BY 1; CONCAT(a, b) count(distinct a) abcdef 1 hijklm 1 SELECT 1 FROM t1 GROUP BY CONCAT(a, b); 1 1 1 INSERT INTO t1 values ('hij','klm'); SELECT CONCAT(a, b),count(*) FROM t1 GROUP BY 1; CONCAT(a, b) count(*) abcdef 1 hijklm 2 DROP TABLE t1; create table t1 (One int unsigned, Two int unsigned, Three int unsigned, Four int unsigned); insert into t1 values (1,2,1,4),(1,2,2,4),(1,2,3,4),(1,2,4,4),(1,1,1,4),(1,1,2,4),(1,1,3,4),(1,1,4,4),(1,3,1,4),(1,3,2,4),(1,3,3,4),(1,3,4,4); select One, Two, sum(Four) from t1 group by One,Two; One Two sum(Four) 1 1 16 1 2 16 1 3 16 drop table t1; create table t1 (id integer primary key not null auto_increment, gender char(1)); insert into t1 values (NULL, 'M'), (NULL, 'F'),(NULL, 'F'),(NULL, 'F'),(NULL, 'M'); create table t2 (user_id integer not null, date date); insert into t2 values (1, '2002-06-09'),(2, '2002-06-09'),(1, '2002-06-09'),(3, '2002-06-09'),(4, '2002-06-09'),(4, '2002-06-09'); select u.gender as gender, count(distinct u.id) as dist_count, (count(distinct u.id)/5*100) as percentage from t1 u, t2 l where l.user_id = u.id group by u.gender; gender dist_count percentage F 3 60.00 M 1 20.00 select u.gender as gender, count(distinct u.id) as dist_count, (count(distinct u.id)/5*100) as percentage from t1 u, t2 l where l.user_id = u.id group by u.gender order by percentage; gender dist_count percentage M 1 20.00 F 3 60.00 drop table t1,t2; CREATE TABLE t1 (ID1 int, ID2 int, ID int NOT NULL AUTO_INCREMENT,PRIMARY KEY(ID )); insert into t1 values (1,244,NULL),(2,243,NULL),(134,223,NULL),(185,186,NULL); select S.ID as xID, S.ID1 as xID1 from t1 as S left join t1 as yS on S.ID1 between yS.ID1 and yS.ID2; xID xID1 1 1 2 2 2 2 3 134 3 134 3 134 4 185 4 185 4 185 4 185 select S.ID as xID, S.ID1 as xID1, repeat('*',count(distinct yS.ID)) as Level from t1 as S left join t1 as yS on S.ID1 between yS.ID1 and yS.ID2 group by xID order by xID1; xID xID1 Level 1 1 * 2 2 ** 3 134 *** 4 185 **** drop table t1; CREATE TABLE t1 ( pid int(11) unsigned NOT NULL default '0', c1id int(11) unsigned default NULL, c2id int(11) unsigned default NULL, value int(11) unsigned NOT NULL default '0', UNIQUE KEY pid2 (pid,c1id,c2id), UNIQUE KEY pid (pid,value) ) ENGINE=MyISAM; INSERT INTO t1 VALUES (1, 1, NULL, 1),(1, 2, NULL, 2),(1, NULL, 3, 3),(1, 4, NULL, 4),(1, 5, NULL, 5); CREATE TABLE t2 ( id int(11) unsigned NOT NULL default '0', active enum('Yes','No') NOT NULL default 'Yes', PRIMARY KEY (id) ) ENGINE=MyISAM; INSERT INTO t2 VALUES (1, 'Yes'),(2, 'No'),(4, 'Yes'),(5, 'No'); CREATE TABLE t3 ( id int(11) unsigned NOT NULL default '0', active enum('Yes','No') NOT NULL default 'Yes', PRIMARY KEY (id) ); INSERT INTO t3 VALUES (3, 'Yes'); select * from t1 AS m LEFT JOIN t2 AS c1 ON m.c1id = c1.id AND c1.active = 'Yes' LEFT JOIN t3 AS c2 ON m.c2id = c2.id AND c2.active = 'Yes' WHERE m.pid=1 AND (c1.id IS NOT NULL OR c2.id IS NOT NULL); pid c1id c2id value id active id active 1 1 NULL 1 1 Yes NULL NULL 1 NULL 3 3 NULL NULL 3 Yes 1 4 NULL 4 4 Yes NULL NULL select max(value) from t1 AS m LEFT JOIN t2 AS c1 ON m.c1id = c1.id AND c1.active = 'Yes' LEFT JOIN t3 AS c2 ON m.c2id = c2.id AND c2.active = 'Yes' WHERE m.pid=1 AND (c1.id IS NOT NULL OR c2.id IS NOT NULL); max(value) 4 drop table t1,t2,t3; create table t1 (a blob null); insert into t1 values (NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(""),(""),(""),("b"); select a,count(*) from t1 group by a; a count(*) NULL 9 3 b 1 set option sql_big_tables=1; select a,count(*) from t1 group by a; a count(*) NULL 9 3 b 1 drop table t1; create table t1 (a int not null, b int not null); insert into t1 values (1,1),(1,2),(3,1),(3,2),(2,2),(2,1); create table t2 (a int not null, b int not null, key(a)); insert into t2 values (1,3),(3,1),(2,2),(1,1); select t1.a,t2.b from t1,t2 where t1.a=t2.a group by t1.a,t2.b; a b 1 1 1 3 2 2 3 1 select t1.a,t2.b from t1,t2 where t1.a=t2.a group by t1.a,t2.b ORDER BY NULL; a b 1 3 3 1 2 2 1 1 explain select t1.a,t2.b from t1,t2 where t1.a=t2.a group by t1.a,t2.b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using temporary; Using filesort 1 SIMPLE t2 ALL a NULL NULL NULL 3 Using where explain select t1.a,t2.b from t1,t2 where t1.a=t2.a group by t1.a,t2.b ORDER BY NULL; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using temporary 1 SIMPLE t2 ALL a NULL NULL NULL 3 Using where drop table t1,t2; create table t1 (a int, b int); insert into t1 values (1, 4),(10, 40),(1, 4),(10, 43),(1, 4),(10, 41),(1, 4),(10, 43),(1, 4); select a, MAX(b), INTERVAL (MAX(b), 1,3,10,30,39,40,50,60,100,1000) from t1 group by a; a MAX(b) INTERVAL (MAX(b), 1,3,10,30,39,40,50,60,100,1000) 1 4 2 10 43 6 select a, MAX(b), CASE MAX(b) when 4 then 4 when 43 then 43 else 0 end from t1 group by a; a MAX(b) CASE MAX(b) when 4 then 4 when 43 then 43 else 0 end 1 4 4 10 43 43 select a, MAX(b), FIELD(MAX(b), '43', '4', '5') from t1 group by a; a MAX(b) FIELD(MAX(b), '43', '4', '5') 1 4 2 10 43 1 select a, MAX(b), CONCAT_WS(MAX(b), '43', '4', '5') from t1 group by a; a MAX(b) CONCAT_WS(MAX(b), '43', '4', '5') 1 4 434445 10 43 43434435 select a, MAX(b), ELT(MAX(b), 'a', 'b', 'c', 'd', 'e', 'f') from t1 group by a; a MAX(b) ELT(MAX(b), 'a', 'b', 'c', 'd', 'e', 'f') 1 4 d 10 43 NULL select a, MAX(b), MAKE_SET(MAX(b), 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h') from t1 group by a; a MAX(b) MAKE_SET(MAX(b), 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h') 1 4 c 10 43 a,b,d,f drop table t1; create table t1 (id int not null, qty int not null); insert into t1 values (1,2),(1,3),(2,4),(2,5); select id, sum(qty) as sqty, count(qty) as cqty from t1 group by id having sum(qty)>2 and cqty>1; id sqty cqty 1 5 2 2 9 2 select id, sum(qty) as sqty from t1 group by id having sqty>2 and count(qty)>1; id sqty 1 5 2 9 select id, sum(qty) as sqty, count(qty) as cqty from t1 group by id having sqty>2 and cqty>1; id sqty cqty 1 5 2 2 9 2 select id, sum(qty) as sqty, count(qty) as cqty from t1 group by id having sum(qty)>2 and count(qty)>1; id sqty cqty 1 5 2 2 9 2 select count(*), case interval(qty,2,3,4,5,6,7,8) when -1 then NULL when 0 then "zero" when 1 then "one" when 2 then "two" end as category from t1 group by category; count(*) category 2 NULL 1 one 1 two select count(*), interval(qty,2,3,4,5,6,7,8) as category from t1 group by category; count(*) category 1 1 1 2 1 3 1 4 drop table t1; CREATE TABLE t1 ( userid int(10) unsigned, score smallint(5) unsigned, key (score) ); INSERT INTO t1 VALUES (1,1),(2,2),(1,1),(3,3),(3,3),(3,3),(3,3),(3,3); SELECT userid,count(*) FROM t1 GROUP BY userid DESC; userid count(*) 3 5 2 1 1 2 EXPLAIN SELECT userid,count(*) FROM t1 GROUP BY userid DESC; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 8 Using temporary; Using filesort DROP TABLE t1; CREATE TABLE t1 ( i int(11) default NULL, j int(11) default NULL ); INSERT INTO t1 VALUES (1,2),(2,3),(4,5),(3,5),(1,5),(23,5); SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL; i COUNT(DISTINCT(i)) 1 1 2 1 4 4 explain SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort DROP TABLE t1; create table t1 (a int); insert into t1 values(null); select min(a) is null from t1; min(a) is null 1 select min(a) is null or null from t1; min(a) is null or null 1 select 1 and min(a) is null from t1; 1 and min(a) is null 1 drop table t1; create table t1 ( col1 int, col2 int ); insert into t1 values (1,1),(1,2),(1,3),(2,1),(2,2); select group_concat( distinct col1 ) as alias from t1 group by col2 having alias like '%'; alias 1,2 1,2 1 drop table t1; create table t1 (a integer, b integer, c integer); insert into t1 (a,b) values (1,2),(1,3),(2,5); select a, 0.1*0+1 r2, sum(1) r1 from t1 where a = 1 group by a having r1>1 and r2=1; a r2 r1 1 1.0 2 select a, round(rand(100)*10) r2, sum(1) r1 from t1 where a = 1 group by a having r1>1 and r2<=2; a r2 r1 1 2 2 select a,sum(b) from t1 where a=1 group by c; a sum(b) 1 5 select a*sum(b) from t1 where a=1 group by c; a*sum(b) 5 select sum(a)*sum(b) from t1 where a=1 group by c; sum(a)*sum(b) 10 select a,sum(b) from t1 where a=1 group by c having a=1; a sum(b) 1 5 select a as d,sum(b) from t1 where a=1 group by c having d=1; d sum(b) 1 5 select sum(a)*sum(b) as d from t1 where a=1 group by c having d > 0; d 10 drop table t1; create table t1(a int); insert into t1 values (0),(1),(2),(3),(4),(5),(6),(8),(9); create table t2 ( a int, b varchar(200) NOT NULL, c varchar(50) NOT NULL, d varchar(100) NOT NULL, primary key (a,b(132),c,d), key a (a,b) ) charset=utf8; insert into t2 select x3.a, -- 3 concat('val-', x3.a + 3*x4.a), -- 12 concat('val-', @a:=x3.a + 3*x4.a + 12*C.a), -- 120 concat('val-', @a + 120*D.a) from t1 x3, t1 x4, t1 C, t1 D where x3.a < 3 and x4.a < 4 and D.a < 4; delete from t2 where a = 2 and b = 'val-2' order by a,b,c,d limit 30; explain select c from t2 where a = 2 and b = 'val-2' group by c; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ref PRIMARY,a PRIMARY 400 const,const 6 Using where select c from t2 where a = 2 and b = 'val-2' group by c; c val-74 val-98 drop table t1,t2; create table t1 (b int4 unsigned not null); insert into t1 values(3000000000); select * from t1; b 3000000000 select min(b) from t1; min(b) 3000000000 drop table t1; CREATE TABLE t1 (id int PRIMARY KEY, user_id int, hostname longtext); INSERT INTO t1 VALUES (1, 7, 'cache-dtc-af05.proxy.aol.com'), (2, 3, 'what.ever.com'), (3, 7, 'cache-dtc-af05.proxy.aol.com'), (4, 7, 'cache-dtc-af05.proxy.aol.com'); SELECT hostname, COUNT(DISTINCT user_id) as no FROM t1 WHERE hostname LIKE '%aol%' GROUP BY hostname; hostname no cache-dtc-af05.proxy.aol.com 1 DROP TABLE t1; CREATE TABLE t1 (a int, b int); INSERT INTO t1 VALUES (1,2), (1,3); SELECT a, b FROM t1 GROUP BY 'const'; a b 1 2 SELECT DISTINCT a, b FROM t1 GROUP BY 'const'; a b 1 2 DROP TABLE t1; CREATE TABLE t1 (id INT, dt DATETIME); INSERT INTO t1 VALUES ( 1, '2005-05-01 12:30:00' ); INSERT INTO t1 VALUES ( 1, '2005-05-01 12:30:00' ); INSERT INTO t1 VALUES ( 1, '2005-05-01 12:30:00' ); INSERT INTO t1 VALUES ( 1, '2005-05-01 12:30:00' ); SELECT dt DIV 1 AS f, id FROM t1 GROUP BY f; f id 20050501123000 1 DROP TABLE t1; CREATE TABLE t1 (id varchar(20) NOT NULL); INSERT INTO t1 VALUES ('trans1'), ('trans2'); CREATE TABLE t2 (id varchar(20) NOT NULL, err_comment blob NOT NULL); INSERT INTO t2 VALUES ('trans1', 'a problem'); SELECT COUNT(DISTINCT(t1.id)), LEFT(err_comment, 256) AS err_comment FROM t1 LEFT JOIN t2 ON t1.id=t2.id GROUP BY err_comment; COUNT(DISTINCT(t1.id)) err_comment 1 NULL 1 a problem DROP TABLE t1, t2;