call mtr.add_suppression("Sort aborted.*"); call mtr.add_suppression("Out of sort memory; increase server sort buffer size"); CREATE TABLE t1 ( id int(6) DEFAULT '0' NOT NULL, idservice int(5), clee char(20) NOT NULL, flag char(1), KEY id (id), PRIMARY KEY (clee) ); INSERT INTO t1 VALUES (2,4,'6067169d','Y'); INSERT INTO t1 VALUES (2,5,'606716d1','Y'); INSERT INTO t1 VALUES (2,1,'606717c1','Y'); INSERT INTO t1 VALUES (3,1,'6067178d','Y'); INSERT INTO t1 VALUES (2,6,'60671515','Y'); INSERT INTO t1 VALUES (2,7,'60671569','Y'); INSERT INTO t1 VALUES (2,3,'dd','Y'); CREATE TABLE t2 ( id int(6) NOT NULL auto_increment, description varchar(40) NOT NULL, idform varchar(40), ordre int(6) unsigned DEFAULT '0' NOT NULL, image varchar(60), PRIMARY KEY (id), KEY id (id,ordre) ); INSERT INTO t2 VALUES (1,'Emettre un appel d''offres','en_construction.html',10,'emettre.gif'); INSERT INTO t2 VALUES (2,'Emettre des soumissions','en_construction.html',20,'emettre.gif'); INSERT INTO t2 VALUES (7,'Liste des t2','t2_liste_form.phtml',51060,'link.gif'); INSERT INTO t2 VALUES (8,'Consulter les soumissions','consulter_soumissions.phtml',200,'link.gif'); INSERT INTO t2 VALUES (9,'Ajouter un type de materiel','typeMateriel_ajoute_form.phtml',51000,'link.gif'); INSERT INTO t2 VALUES (10,'Lister/modifier un type de materiel','typeMateriel_liste_form.phtml',51010,'link.gif'); INSERT INTO t2 VALUES (3,'Créer une fiche de client','clients_ajoute_form.phtml',40000,'link.gif'); INSERT INTO t2 VALUES (4,'Modifier des clients','en_construction.html',40010,'link.gif'); INSERT INTO t2 VALUES (5,'Effacer des clients','en_construction.html',40020,'link.gif'); INSERT INTO t2 VALUES (6,'Ajouter un service','t2_ajoute_form.phtml',51050,'link.gif'); select t1.id,t1.idservice,t2.ordre,t2.description from t1, t2 where t1.id = 2 and t1.idservice = t2.id order by t2.ordre; id idservice ordre description 2 1 10 Emettre un appel d'offres 2 3 40000 Créer une fiche de client 2 4 40010 Modifier des clients 2 5 40020 Effacer des clients 2 6 51050 Ajouter un service 2 7 51060 Liste des t2 drop table t1,t2; create table t1 (first char(10),last char(10)); insert into t1 values ("Michael","Widenius"); insert into t1 values ("Allan","Larsson"); insert into t1 values ("David","Axmark"); select concat(first," ",last) as name from t1 order by name; name Allan Larsson David Axmark Michael Widenius select concat(last," ",first) as name from t1 order by name; name Axmark David Larsson Allan Widenius Michael drop table t1; create table t1 (i int); insert into t1 values(1),(2),(1),(2),(1),(2),(3); select distinct i from t1; i 1 2 3 select distinct i from t1 order by rand(5); i 1 3 2 select distinct i from t1 order by i desc; i 3 2 1 select distinct i from t1 order by 1-i; i 3 2 1 select distinct i from t1 order by mod(i,2),i; i 2 1 3 drop table t1; create table t1 ( pk int primary key, name varchar(255) not null, number varchar(255) not null); insert into t1 values (1, 'Gamma', '123'), (2, 'Gamma Ext', '123a'), (3, 'Alpha', '001'), (4, 'Beta', '200c'); select distinct t1.name as 'Building Name',t1.number as 'Building Number' from t1 order by t1.name asc; Building Name Building Number Alpha 001 Beta 200c Gamma 123 Gamma Ext 123a drop table t1; create table t1 (id int not null,col1 int not null,col2 int not null,index(col1)); insert into t1 values(1,2,2),(2,2,1),(3,1,2),(4,1,1),(5,1,4),(6,2,3),(7,3,1),(8,2,4); select * from t1 order by col1,col2; id col1 col2 4 1 1 3 1 2 5 1 4 2 2 1 1 2 2 6 2 3 8 2 4 7 3 1 select col1 from t1 order by id; col1 2 2 1 1 1 2 3 2 select col1 as id from t1 order by id; id 1 1 1 2 2 2 2 3 select concat(col1) as id from t1 order by id; id 1 1 1 2 2 2 2 3 drop table t1; CREATE TABLE t1 (id int auto_increment primary key,aika varchar(40),aikakentta timestamp); insert into t1 (aika) values ('Keskiviikko'); insert into t1 (aika) values ('Tiistai'); insert into t1 (aika) values ('Maanantai'); insert into t1 (aika) values ('Sunnuntai'); SELECT FIELD(SUBSTRING(t1.aika,1,2),'Ma','Ti','Ke','To','Pe','La','Su') AS test FROM t1 ORDER by test; test 1 2 3 7 drop table t1; CREATE TABLE t1 ( a int unsigned NOT NULL, b int unsigned NOT NULL, c int unsigned NOT NULL, UNIQUE(a), INDEX(b), INDEX(c) ); CREATE TABLE t2 ( c int unsigned NOT NULL, i int unsigned NOT NULL, INDEX(c) ); CREATE TABLE t3 ( c int unsigned NOT NULL, v varchar(64), INDEX(c) ); INSERT INTO t1 VALUES (1,1,1); INSERT INTO t1 VALUES (2,1,2); INSERT INTO t1 VALUES (3,2,1); INSERT INTO t1 VALUES (4,2,2); INSERT INTO t2 VALUES (1,50); INSERT INTO t2 VALUES (2,25); INSERT INTO t3 VALUES (1,'123 Park Place'); INSERT INTO t3 VALUES (2,'453 Boardwalk'); SET @save_optimizer_switch=@@optimizer_switch; SET optimizer_switch='outer_join_with_cache=off'; SELECT a,b,if(b = 1,i,if(b = 2,v,'')) FROM t1 LEFT JOIN t2 USING(c) LEFT JOIN t3 ON t3.c = t1.c; a b if(b = 1,i,if(b = 2,v,'')) 1 1 50 2 1 25 3 2 123 Park Place 4 2 453 Boardwalk SELECT a,b,if(b = 1,i,if(b = 2,v,'')) FROM t1 LEFT JOIN t2 ON t1.c = t2.c LEFT JOIN t3 ON t3.c = t1.c; a b if(b = 1,i,if(b = 2,v,'')) 1 1 50 2 1 25 3 2 123 Park Place 4 2 453 Boardwalk SELECT a,b,if(b = 1,i,if(b = 2,v,'')) FROM t1 LEFT JOIN t2 USING(c) LEFT JOIN t3 ON t3.c = t1.c ORDER BY a; a b if(b = 1,i,if(b = 2,v,'')) 1 1 50 2 1 25 3 2 123 Park Place 4 2 453 Boardwalk SELECT a,b,if(b = 1,i,if(b = 2,v,'')) FROM t1 LEFT JOIN t2 ON t1.c = t2.c LEFT JOIN t3 ON t3.c = t1.c ORDER BY a; a b if(b = 1,i,if(b = 2,v,'')) 1 1 50 2 1 25 3 2 123 Park Place 4 2 453 Boardwalk SET optimizer_switch=@save_optimizer_switch; drop table t1,t2,t3; create table t1 (ID int not null primary key, TransactionID int not null); insert into t1 (ID, TransactionID) values (1, 87), (2, 89), (3, 92), (4, 94), (5, 486), (6, 490), (7, 753), (9, 828), (10, 832), (11, 834), (12, 840); create table t2 (ID int not null primary key, GroupID int not null); insert into t2 (ID, GroupID) values (87, 87), (89, 89), (92, 92), (94, 94), (486, 486), (490, 490),(753, 753), (828, 828), (832, 832), (834, 834), (840, 840); create table t3 (ID int not null primary key, DateOfAction date not null); insert into t3 (ID, DateOfAction) values (87, '1999-07-19'), (89, '1999-07-19'), (92, '1999-07-19'), (94, '1999-07-19'), (486, '1999-07-18'), (490, '2000-03-27'), (753, '2000-03-28'), (828, '1999-07-27'), (832, '1999-07-27'),(834, '1999-07-27'), (840, '1999-07-27'); select t3.DateOfAction, t1.TransactionID from t1 join t2 join t3 where t2.ID = t1.TransactionID and t3.ID = t2.GroupID order by t3.DateOfAction, t1.TransactionID; DateOfAction TransactionID 1999-07-18 486 1999-07-19 87 1999-07-19 89 1999-07-19 92 1999-07-19 94 1999-07-27 828 1999-07-27 832 1999-07-27 834 1999-07-27 840 2000-03-27 490 2000-03-28 753 select t3.DateOfAction, t1.TransactionID from t1 join t2 join t3 where t2.ID = t1.TransactionID and t3.ID = t2.GroupID order by t1.TransactionID,t3.DateOfAction; DateOfAction TransactionID 1999-07-19 87 1999-07-19 89 1999-07-19 92 1999-07-19 94 1999-07-18 486 2000-03-27 490 2000-03-28 753 1999-07-27 828 1999-07-27 832 1999-07-27 834 1999-07-27 840 drop table t1,t2,t3; CREATE TABLE t1 ( member_id int(11) NOT NULL auto_increment, inschrijf_datum varchar(20) NOT NULL default '', lastchange_datum varchar(20) NOT NULL default '', nickname varchar(20) NOT NULL default '', password varchar(8) NOT NULL default '', voornaam varchar(30) NOT NULL default '', tussenvoegsels varchar(10) NOT NULL default '', achternaam varchar(50) NOT NULL default '', straat varchar(100) NOT NULL default '', postcode varchar(10) NOT NULL default '', wijk varchar(40) NOT NULL default '', plaats varchar(50) NOT NULL default '', telefoon varchar(10) NOT NULL default '', geboortedatum date NOT NULL default '0000-00-00', geslacht varchar(5) NOT NULL default '', email varchar(80) NOT NULL default '', uin varchar(15) NOT NULL default '', homepage varchar(100) NOT NULL default '', internet varchar(15) NOT NULL default '', scherk varchar(30) NOT NULL default '', favo_boek varchar(50) NOT NULL default '', favo_tijdschrift varchar(50) NOT NULL default '', favo_tv varchar(50) NOT NULL default '', favo_eten varchar(50) NOT NULL default '', favo_muziek varchar(30) NOT NULL default '', info text NOT NULL default '', ipnr varchar(30) NOT NULL default '', PRIMARY KEY (member_id) ) ENGINE=MyISAM PACK_KEYS=1; insert into t1 (member_id) values (1),(2),(3); select member_id, nickname, voornaam FROM t1 ORDER by lastchange_datum DESC LIMIT 2; member_id nickname voornaam 1 2 drop table t1; create table t1 (a int not null, b int, c varchar(10), key (a, b, c)); insert into t1 values (1, NULL, NULL), (1, NULL, 'b'), (1, 1, NULL), (1, 1, 'b'), (1, 1, 'b'), (2, 1, 'a'), (2, 1, 'b'), (2, 2, 'a'), (2, 2, 'b'), (2, 3, 'c'),(1,3,'b'); insert into t1 select * from t1; explain select * from t1 where (a = 1 and b is null and c = 'b') or (a > 2) order by a desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 22 NULL 3 Using where; Using index select * from t1 where (a = 1 and b is null and c = 'b') or (a > 2) order by a desc; a b c 1 NULL b 1 NULL b explain select * from t1 where a >= 1 and a < 3 order by a desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 4 NULL 22 Using where; Using index select * from t1 where a >= 1 and a < 3 order by a desc; a b c 2 3 c 2 3 c 2 2 b 2 2 b 2 2 a 2 2 a 2 1 b 2 1 b 2 1 a 2 1 a 1 3 b 1 3 b 1 1 b 1 1 b 1 1 b 1 1 b 1 1 NULL 1 1 NULL 1 NULL b 1 NULL b 1 NULL NULL 1 NULL NULL explain select * from t1 where a = 1 order by a desc, b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref a a 4 const 12 Using where; Using index select * from t1 where a = 1 order by a desc, b desc; a b c 1 3 b 1 3 b 1 1 b 1 1 b 1 1 b 1 1 b 1 1 NULL 1 1 NULL 1 NULL b 1 NULL b 1 NULL NULL 1 NULL NULL explain select * from t1 where a = 1 and b is null order by a desc, b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref a a 9 const,const 4 Using where; Using index; Using filesort select * from t1 where a = 1 and b is null order by a desc, b desc; a b c 1 NULL NULL 1 NULL NULL 1 NULL b 1 NULL b explain select * from t1 where a >= 1 and a < 3 and b >0 order by a desc,b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 9 NULL 18 Using where; Using index explain select * from t1 where a = 2 and b >0 order by a desc,b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 9 NULL 10 Using where; Using index explain select * from t1 where a = 2 and b is null order by a desc,b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref a a 9 const,const 1 Using where; Using index; Using filesort explain select * from t1 where a = 2 and (b is null or b > 0) order by a desc,b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 9 NULL 11 Using where; Using index explain select * from t1 where a = 2 and b > 0 order by a desc,b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 9 NULL 10 Using where; Using index explain select * from t1 where a = 2 and b < 2 order by a desc,b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 9 NULL 4 Using where; Using index explain select * from t1 where a = 1 order by b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref a a 4 const 12 Using where; Using index explain select * from t1 where a = 2 and b > 0 order by a desc,b desc,b,a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 9 NULL 10 Using where; Using index explain select * from t1 where a = 2 and b < 2 order by a desc,a,b desc,a,b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 9 NULL 4 Using where; Using index select * from t1 where a = 1 order by b desc; a b c 1 3 b 1 3 b 1 1 b 1 1 b 1 1 b 1 1 b 1 1 NULL 1 1 NULL 1 NULL b 1 NULL b 1 NULL NULL 1 NULL NULL SET STATEMENT sql_mode = 'NO_ENGINE_SUBSTITUTION' FOR alter table t1 modify b int not null, modify c varchar(10) not null; Warnings: Warning 1265 Data truncated for column 'b' at row 1 Warning 1265 Data truncated for column 'c' at row 1 Warning 1265 Data truncated for column 'b' at row 2 Warning 1265 Data truncated for column 'c' at row 3 Warning 1265 Data truncated for column 'b' at row 12 Warning 1265 Data truncated for column 'c' at row 12 Warning 1265 Data truncated for column 'b' at row 13 Warning 1265 Data truncated for column 'c' at row 14 explain select * from t1 order by a, b, c; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL a 20 NULL 22 Using index select * from t1 order by a, b, c; a b c 1 0 1 0 1 0 b 1 0 b 1 1 1 1 1 1 b 1 1 b 1 1 b 1 1 b 1 3 b 1 3 b 2 1 a 2 1 a 2 1 b 2 1 b 2 2 a 2 2 a 2 2 b 2 2 b 2 3 c 2 3 c explain select * from t1 order by a desc, b desc, c desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL a 20 NULL 22 Using index select * from t1 order by a desc, b desc, c desc; a b c 2 3 c 2 3 c 2 2 b 2 2 b 2 2 a 2 2 a 2 1 b 2 1 b 2 1 a 2 1 a 1 3 b 1 3 b 1 1 b 1 1 b 1 1 b 1 1 b 1 1 1 1 1 0 b 1 0 b 1 0 1 0 explain select * from t1 where (a = 1 and b = 1 and c = 'b') or (a > 2) order by a desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 20 NULL 5 Using where; Using index select * from t1 where (a = 1 and b = 1 and c = 'b') or (a > 2) order by a desc; a b c 1 1 b 1 1 b 1 1 b 1 1 b explain select * from t1 where a < 2 and b <= 1 order by a desc, b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 4 NULL 12 Using where; Using index select * from t1 where a < 2 and b <= 1 order by a desc, b desc; a b c 1 1 b 1 1 b 1 1 b 1 1 b 1 1 1 1 1 0 b 1 0 b 1 0 1 0 select count(*) from t1 where a < 5 and b > 0; count(*) 18 select * from t1 where a < 5 and b > 0 order by a desc,b desc; a b c 2 3 c 2 3 c 2 2 b 2 2 b 2 2 a 2 2 a 2 1 b 2 1 b 2 1 a 2 1 a 1 3 b 1 3 b 1 1 b 1 1 b 1 1 b 1 1 b 1 1 1 1 explain select * from t1 where a between 1 and 3 and b <= 1 order by a desc, b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 8 NULL 22 Using where; Using index select * from t1 where a between 1 and 3 and b <= 1 order by a desc, b desc; a b c 2 1 b 2 1 b 2 1 a 2 1 a 1 1 b 1 1 b 1 1 b 1 1 b 1 1 1 1 1 0 b 1 0 b 1 0 1 0 explain select * from t1 where a between 0 and 1 order by a desc, b desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 4 NULL 12 Using where; Using index select * from t1 where a between 0 and 1 order by a desc, b desc; a b c 1 3 b 1 3 b 1 1 b 1 1 b 1 1 b 1 1 b 1 1 1 1 1 0 b 1 0 b 1 0 1 0 drop table t1; CREATE TABLE t1 ( gid int(10) unsigned NOT NULL auto_increment, cid smallint(5) unsigned NOT NULL default '0', PRIMARY KEY (gid), KEY component_id (cid) ) ENGINE=MyISAM; INSERT INTO t1 VALUES (103853,108),(103867,108),(103962,108),(104505,108),(104619,108),(104620,108); ALTER TABLE t1 add skr int(10) not null; CREATE TABLE t2 ( gid int(10) unsigned NOT NULL default '0', uid smallint(5) unsigned NOT NULL default '1', sid tinyint(3) unsigned NOT NULL default '1', PRIMARY KEY (gid), KEY uid (uid), KEY status_id (sid) ) ENGINE=MyISAM; INSERT INTO t2 VALUES (103853,250,5),(103867,27,5),(103962,27,5),(104505,117,5),(104619,75,5),(104620,15,5); CREATE TABLE t3 ( uid smallint(6) NOT NULL auto_increment, PRIMARY KEY (uid) ) ENGINE=MyISAM; INSERT INTO t3 VALUES (1),(15),(27),(75),(117),(250); ALTER TABLE t3 add skr int(10) not null; select t1.gid, t2.sid, t3.uid from t2, t1, t3 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid; gid sid uid 104620 5 15 103867 5 27 103962 5 27 104619 5 75 104505 5 117 103853 5 250 select t1.gid, t2.sid, t3.uid from t3, t2, t1 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid; gid sid uid 104620 5 15 103867 5 27 103962 5 27 104619 5 75 104505 5 117 103853 5 250 EXPLAIN select t1.gid, t2.sid, t3.uid from t3, t2, t1 where t2.gid = t1.gid and t2.uid = t3.uid order by t1.gid, t3.uid; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ALL PRIMARY,uid NULL NULL NULL 6 Using temporary; Using filesort 1 SIMPLE t3 eq_ref PRIMARY PRIMARY 2 test.t2.uid 1 Using where; Using index 1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.gid 1 Using index EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.gid = t3.uid order by t1.gid,t3.skr; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t3 ALL PRIMARY NULL NULL NULL 6 Using temporary; Using filesort 1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t3.uid 1 Using where; Using index EXPLAIN SELECT t1.gid, t2.sid, t3.uid from t2, t1, t3 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ALL PRIMARY,uid NULL NULL NULL 6 Using temporary; Using filesort 1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.gid 1 Using index 1 SIMPLE t3 eq_ref PRIMARY PRIMARY 2 test.t2.uid 1 Using where; Using index EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.gid = t3.uid order by t3.skr,t1.gid; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t3 ALL PRIMARY NULL NULL NULL 6 Using temporary; Using filesort 1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t3.uid 1 Using where; Using index EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.skr = t3.uid order by t1.gid,t3.skr; 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 t3 eq_ref PRIMARY PRIMARY 2 test.t1.skr 1 Using index condition drop table t1,t2,t3; CREATE TABLE t1 ( `titre` char(80) NOT NULL default '', `numeropost` mediumint(8) unsigned NOT NULL auto_increment, `date` datetime NOT NULL default '0000-00-00 00:00:00', `auteur` char(35) NOT NULL default '', `icone` tinyint(2) unsigned NOT NULL default '0', `lastauteur` char(35) NOT NULL default '', `nbrep` smallint(6) unsigned NOT NULL default '0', `dest` char(35) NOT NULL default '', `lu` tinyint(1) unsigned NOT NULL default '0', `vue` mediumint(8) unsigned NOT NULL default '0', `ludest` tinyint(1) unsigned NOT NULL default '0', `ouvert` tinyint(1) unsigned NOT NULL default '1', PRIMARY KEY (`numeropost`), KEY `date` (`date`), KEY `dest` (`dest`,`ludest`), KEY `auteur` (`auteur`,`lu`), KEY `auteur_2` (`auteur`,`date`), KEY `dest_2` (`dest`,`date`) ) CHECKSUM=1; CREATE TABLE t2 ( `numeropost` mediumint(8) unsigned NOT NULL default '0', `pseudo` char(35) NOT NULL default '', PRIMARY KEY (`numeropost`,`pseudo`), KEY `pseudo` (`pseudo`) ); INSERT INTO t1 (titre,auteur,dest) VALUES ('test','joce','bug'); INSERT INTO t2 (numeropost,pseudo) VALUES (1,'joce'),(1,'bug'); SELECT titre,t1.numeropost,auteur,icone,nbrep,0,date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30; titre numeropost auteur icone nbrep 0 date vue ouvert lastauteur dest test 1 joce 0 0 0 0000-00-00 00:00:00 0 1 bug SELECT titre,numeropost,auteur,icone,nbrep,0,date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30; titre numeropost auteur icone nbrep 0 date vue ouvert lastauteur dest test 1 joce 0 0 0 0000-00-00 00:00:00 0 1 bug SELECT titre,t1.numeropost,auteur,icone,nbrep,'0',date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30; titre numeropost auteur icone nbrep 0 date vue ouvert lastauteur dest test 1 joce 0 0 0 0000-00-00 00:00:00 0 1 bug SELECT titre,numeropost,auteur,icone,nbrep,'0',date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30; titre numeropost auteur icone nbrep 0 date vue ouvert lastauteur dest test 1 joce 0 0 0 0000-00-00 00:00:00 0 1 bug drop table t1,t2; CREATE TABLE t1 (a int, b int); INSERT INTO t1 VALUES (1, 2); INSERT INTO t1 VALUES (3, 4); INSERT INTO t1 VALUES (5, NULL); SELECT * FROM t1 ORDER BY b; a b 5 NULL 1 2 3 4 SELECT * FROM t1 ORDER BY b DESC; a b 3 4 1 2 5 NULL SELECT * FROM t1 ORDER BY (a + b); a b 5 NULL 1 2 3 4 SELECT * FROM t1 ORDER BY (a + b) DESC; a b 3 4 1 2 5 NULL DROP TABLE t1; create table t1(id int not null auto_increment primary key, t char(12)); explain select id,t from t1 order by id; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 Using filesort explain select id,t from t1 force index (primary) order by id; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL PRIMARY 4 NULL 1000 drop table t1; CREATE TABLE t1 ( FieldKey varchar(36) NOT NULL default '', LongVal bigint(20) default NULL, StringVal mediumtext, KEY FieldKey (FieldKey), KEY LongField (FieldKey,LongVal), KEY StringField (FieldKey,StringVal(32)) ); INSERT INTO t1 VALUES ('0',3,'0'),('0',2,'1'),('0',1,'2'),('1',2,'1'),('1',1,'3'), ('1',0,'2'),('2',3,'0'),('2',2,'1'),('2',1,'2'),('2',3,'0'),('2',2,'1'),('2',1,'2'),('3',2,'1'),('3',1,'2'),('3','3','3'); EXPLAIN SELECT * FROM t1 WHERE FieldKey = '1' ORDER BY LongVal; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref FieldKey,LongField,StringField LongField 38 const 3 Using where SELECT * FROM t1 WHERE FieldKey = '1' ORDER BY LongVal; FieldKey LongVal StringVal 1 0 2 1 1 3 1 2 1 DS-MRR: use two IGNORE INDEX queries, otherwise we get cost races, because DS-MRR: records_in_range/read_time return the same numbers for all three indexes EXPLAIN SELECT * FROM t1 IGNORE INDEX (LongField, StringField) WHERE FieldKey > '2' ORDER BY LongVal; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range FieldKey FieldKey 38 NULL 3 Using index condition; Using filesort EXPLAIN SELECT * FROM t1 IGNORE INDEX (FieldKey, LongField) WHERE FieldKey > '2' ORDER BY LongVal; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range StringField StringField 38 NULL 3 Using where; Using filesort SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY LongVal; FieldKey LongVal StringVal 3 1 2 3 2 1 3 3 3 EXPLAIN SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY FieldKey, LongVal; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range FieldKey,LongField,StringField LongField 38 NULL 3 Using where SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY FieldKey, LongVal; FieldKey LongVal StringVal 3 1 2 3 2 1 3 3 3 DROP TABLE t1; CREATE TABLE t1 (a INT, b INT); SET @id=0; UPDATE t1 SET a=0 ORDER BY (a=@id), b; DROP TABLE t1; CREATE TABLE t1 ( id smallint(6) unsigned NOT NULL default '0', menu tinyint(4) NOT NULL default '0', KEY id (id), KEY menu (menu)) ENGINE=MyISAM; INSERT INTO t1 VALUES (11384, 2),(11392, 2); SELECT id FROM t1 WHERE id <11984 AND menu =2 ORDER BY id DESC LIMIT 1 ; id 11392 drop table t1; create table t1(a int, b int, index(b)); insert into t1 values (2, 1), (1, 1), (4, NULL), (3, NULL), (6, 2), (5, 2); insert into t1 values (12, 11), (11, 11), (14, 3), (13, 5), (16, 12), (15, 12); explain select * from t1 where b=1 or b is null order by a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref_or_null b b 5 const 4 Using index condition; Using filesort select * from t1 where b=1 or b is null order by a; a b 1 1 2 1 3 NULL 4 NULL explain select * from t1 where b=2 or b is null order by a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref_or_null b b 5 const 4 Using index condition; Using filesort select * from t1 where b=2 or b is null order by a; a b 3 NULL 4 NULL 5 2 6 2 drop table t1; create table t1 (a int not null auto_increment, b int not null, c int not null, d int not null, key(a,b,d), key(c,b,a)); create table t2 like t1; insert into t1 values (NULL, 1, 2, 0), (NULL, 2, 1, 1), (NULL, 3, 4, 2), (NULL, 4, 3, 3); insert into t2 select null, b, c, d from t1; insert into t1 select null, b, c, d from t2; insert into t2 select null, b, c, d from t1; insert into t1 select null, b, c, d from t2; insert into t2 select null, b, c, d from t1; insert into t1 select null, b, c, d from t2; insert into t2 select null, b, c, d from t1; insert into t1 select null, b, c, d from t2; insert into t2 select null, b, c, d from t1; insert into t1 select null, b, c, d from t2; optimize table t1; Table Op Msg_type Msg_text test.t1 optimize status OK set @row=10; insert into t1 select 1, b, c + (@row:=@row - 1) * 10, d - @row from t2 limit 10; select * from t1 where a=1 and b in (1) order by c, b, a; a b c d 1 1 2 0 1 1 12 -1 1 1 52 -5 1 1 92 -9 select * from t1 where a=1 and b in (1); a b c d 1 1 92 -9 1 1 52 -5 1 1 12 -1 1 1 2 0 drop table t1, t2; create table t1 (col1 int, col int); create table t2 (col2 int, col int); insert into t1 values (1,1),(2,2),(3,3); insert into t2 values (1,3),(2,2),(3,1); select t1.* , t2.col as t2_col from t1 left join t2 on (t1.col1=t2.col2) order by col; col1 col t2_col 1 1 3 2 2 2 3 3 1 select col1 as col, col from t1 order by col; ERROR 23000: Column 'col' in order clause is ambiguous select t1.col as c1, t2.col as c2 from t1, t2 where t1.col1=t2.col2 order by col; ERROR 23000: Column 'col' in order clause is ambiguous select t1.col as c1, t2.col as c2 from t1, t2 where t1.col1=t2.col2 order by col; ERROR 23000: Column 'col' in order clause is ambiguous select col1 from t1, t2 where t1.col1=t2.col2 order by col; ERROR 23000: Column 'col' in order clause is ambiguous select t1.col as t1_col, t2.col2 from t1, t2 where t1.col1=t2.col2 order by col; ERROR 23000: Column 'col' in order clause is ambiguous select t1.col as t1_col, t2.col from t1, t2 where t1.col1=t2.col2 order by col; t1_col col 3 1 2 2 1 3 select col2 as c, col as c from t2 order by col; c c 3 1 2 2 1 3 select col2 as col, col as col2 from t2 order by col; col col2 1 3 2 2 3 1 select t2.col2, t2.col, t2.col from t2 order by col; col2 col col 3 1 1 2 2 2 1 3 3 select t2.col2 as col from t2 order by t2.col; col 3 2 1 select t2.col2 as col, t2.col from t2 order by t2.col; col col 3 1 2 2 1 3 select t2.col2, t2.col, t2.col from t2 order by t2.col; col2 col col 3 1 1 2 2 2 1 3 3 drop table t1, t2; create table t1 (a char(70)); insert into t1 set a = repeat('x', 20); insert into t1 set a = concat(repeat('x', 63), 'z'); insert into t1 set a = concat(repeat('x', 63), 'ab'); insert into t1 set a = concat(repeat('x', 63), 'aa'); set max_sort_length=20; Warnings: Warning 1292 Truncated incorrect max_sort_length value: '20' select a from t1 order by a; a xxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxab xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxaa xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxz drop table t1; create table t1 ( `sid` decimal(8,0) default null, `wnid` varchar(11) not null default '', key `wnid14` (`wnid`(4)), key `wnid` (`wnid`) ) engine=myisam default charset=latin1; insert into t1 (`sid`, `wnid`) values ('10100','01019000000'),('37986','01019000000'),('37987','01019010000'), ('37994','01019090000'),('475','02070000000'),('25253','02071100000'), ('25255','02071100000'),('25256','02071110000'),('25258','02071130000'), ('25259','02071190000'),('25260','02071200000'),('25261','02071210000'), ('25262','02071290000'),('25263','02071300000'),('25264','02071310000'), ('25265','02071310000'),('25266','02071320000'),('25267','02071320000'), ('25269','02071330000'),('25270','02071340000'),('25271','02071350000'), ('25272','02071360000'),('25273','02071370000'),('25281','02071391000'), ('25282','02071391000'),('25283','02071399000'),('25284','02071400000'), ('25285','02071410000'),('25286','02071410000'),('25287','02071420000'), ('25288','02071420000'),('25291','02071430000'),('25290','02071440000'), ('25292','02071450000'),('25293','02071460000'),('25294','02071470000'), ('25295','02071491000'),('25296','02071491000'),('25297','02071499000'); explain select * from t1 where wnid like '0101%' order by wnid; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range wnid14,wnid wnid 13 NULL 4 Using where select * from t1 where wnid like '0101%' order by wnid; sid wnid 10100 01019000000 37986 01019000000 37987 01019010000 37994 01019090000 drop table t1; CREATE TABLE t1 (a int); INSERT INTO t1 VALUES (2), (1), (1), (2), (1); SELECT a FROM t1 ORDER BY a; a 1 1 1 2 2 (SELECT a FROM t1) ORDER BY a; a 1 1 1 2 2 DROP TABLE t1; CREATE TABLE t1 (a int, b int); INSERT INTO t1 VALUES (1,30), (2,20), (1,10), (2,30), (1,20), (2,10); (SELECT b,a FROM t1 ORDER BY a,b) ORDER BY b,a; b a 10 1 10 2 20 1 20 2 30 1 30 2 (SELECT b FROM t1 ORDER BY b DESC) ORDER BY b ASC; b 10 10 20 20 30 30 (SELECT b,a FROM t1 ORDER BY b,a) ORDER BY a,b; b a 10 1 20 1 30 1 10 2 20 2 30 2 (SELECT b,a FROM t1 ORDER by b,a LIMIT 3) ORDER by a,b; b a 10 1 20 1 10 2 DROP TABLE t1; CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2); SELECT a + 1 AS num FROM t1 ORDER BY 30 - num; num 3 2 SELECT CONCAT('test', a) AS str FROM t1 ORDER BY UPPER(str); str test1 test2 SELECT a + 1 AS num FROM t1 GROUP BY 30 - num; num 3 2 SELECT a + 1 AS num FROM t1 HAVING 30 - num; num 2 3 SELECT a + 1 AS num, num + 1 FROM t1; ERROR 42S22: Unknown column 'num' in 'field list' SELECT a + 1 AS num, (select num + 2 FROM t1 LIMIT 1) FROM t1; num (select num + 2 FROM t1 LIMIT 1) 2 4 3 5 SELECT a.a + 1 AS num FROM t1 a JOIN t1 b ON num = b.a; ERROR 42S22: Unknown column 'num' in 'on clause' DROP TABLE t1; CREATE TABLE bug25126 ( val int unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY ); UPDATE bug25126 SET MissingCol = MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'field list' UPDATE bug25126 SET val = val ORDER BY MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' UPDATE bug25126 SET val = val ORDER BY val; UPDATE bug25126 SET val = 1 ORDER BY val; UPDATE bug25126 SET val = 1 ORDER BY MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' UPDATE bug25126 SET val = 1 ORDER BY val, MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' UPDATE bug25126 SET val = MissingCol ORDER BY MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' UPDATE bug25126 SET MissingCol = 1 ORDER BY val, MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' UPDATE bug25126 SET MissingCol = 1 ORDER BY MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' UPDATE bug25126 SET MissingCol = val ORDER BY MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' UPDATE bug25126 SET MissingCol = MissingCol ORDER BY MissingCol; ERROR 42S22: Unknown column 'MissingCol' in 'order clause' DROP TABLE bug25126; CREATE TABLE t1 (a int); SELECT p.a AS val, q.a AS val1 FROM t1 p, t1 q ORDER BY val > 1; val val1 SELECT p.a AS val, q.a AS val FROM t1 p, t1 q ORDER BY val; ERROR 23000: Column 'val' in order clause is ambiguous SELECT p.a AS val, q.a AS val FROM t1 p, t1 q ORDER BY val > 1; ERROR 23000: Column 'val' in order clause is ambiguous DROP TABLE t1; CREATE TABLE t1 (a int); INSERT INTO t1 VALUES (3), (2), (4), (1); SELECT a, IF(a IN (2,3), a, a+10) FROM t1 ORDER BY IF(a IN (2,3), a, a+10); a IF(a IN (2,3), a, a+10) 2 2 3 3 1 11 4 14 SELECT a, IF(a NOT IN (2,3), a, a+10) FROM t1 ORDER BY IF(a NOT IN (2,3), a, a+10); a IF(a NOT IN (2,3), a, a+10) 1 1 4 4 2 12 3 13 SELECT a, IF(a IN (2,3), a, a+10) FROM t1 ORDER BY IF(a NOT IN (2,3), a, a+10); a IF(a IN (2,3), a, a+10) 1 11 4 14 2 2 3 3 SELECT a, IF(a BETWEEN 2 AND 3, a, a+10) FROM t1 ORDER BY IF(a BETWEEN 2 AND 3, a, a+10); a IF(a BETWEEN 2 AND 3, a, a+10) 2 2 3 3 1 11 4 14 SELECT a, IF(a NOT BETWEEN 2 AND 3, a, a+10) FROM t1 ORDER BY IF(a NOT BETWEEN 2 AND 3, a, a+10); a IF(a NOT BETWEEN 2 AND 3, a, a+10) 1 1 4 4 2 12 3 13 SELECT a, IF(a BETWEEN 2 AND 3, a, a+10) FROM t1 ORDER BY IF(a NOT BETWEEN 2 AND 3, a, a+10); a IF(a BETWEEN 2 AND 3, a, a+10) 1 11 4 14 2 2 3 3 SELECT IF(a IN (1,2), a, '') as x1, IF(a NOT IN (1,2), a, '') as x2 FROM t1 GROUP BY x1, x2; x1 x2 3 4 1 2 SELECT IF(a IN (1,2), a, '') as x1, IF(a NOT IN (1,2), a, '') as x2 FROM t1 GROUP BY x1, IF(a NOT IN (1,2), a, ''); x1 x2 3 4 1 2 SELECT a, a IN (1,2) FROM t1 ORDER BY a IN (1,2); a a IN (1,2) 3 0 4 0 2 1 1 1 SELECT a FROM t1 ORDER BY a IN (1,2); a 3 4 2 1 SELECT a+10 FROM t1 ORDER BY a IN (1,2); a+10 13 14 12 11 SELECT a, IF(a IN (1,2), a, a+10) FROM t1 ORDER BY IF(a IN (3,4), a, a+10); a IF(a IN (1,2), a, a+10) 3 13 4 14 1 1 2 2 DROP TABLE t1; create table t1 (a int not null, b int not null, c int not null); insert t1 values (1,1,1),(1,1,2),(1,2,1); select a, b from t1 group by a, b order by sum(c); a b 1 2 1 1 drop table t1; CREATE TABLE t1 (a int, b int, PRIMARY KEY (a)); INSERT INTO t1 VALUES (1,1), (2,2), (3,3); explain SELECT t1.b as a, t2.b as c FROM t1 LEFT JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2) ORDER BY c; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using temporary; Using filesort 1 SIMPLE t2 const PRIMARY PRIMARY 4 const 1 Using where SELECT t2.b as c FROM t1 LEFT JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2) ORDER BY c; c NULL NULL 2 explain SELECT t1.b as a, t2.b as c FROM t1 JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2) ORDER BY c; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 1 SIMPLE t2 const PRIMARY PRIMARY 4 const 1 CREATE TABLE t2 LIKE t1; INSERT INTO t2 SELECT * from t1; CREATE TABLE t3 LIKE t1; INSERT INTO t3 SELECT * from t1; CREATE TABLE t4 LIKE t1; INSERT INTO t4 SELECT * from t1; INSERT INTO t1 values (0,0),(4,4); SELECT t2.b FROM t1 LEFT JOIN (t2, t3 LEFT JOIN t4 ON t3.a=t4.a) ON (t1.a=t2.a AND t1.b=t3.b) order by t2.b; b NULL NULL 1 2 3 DROP TABLE t1,t2,t3,t4; create table t1 (a int, b int, c int); insert into t1 values (1,2,3), (9,8,3), (19,4,3), (1,4,9); select a,(sum(b)/sum(c)) as ratio from t1 group by a order by sum(b)/sum(c) asc; a ratio 1 0.5000 19 1.3333 9 2.6667 drop table t1; CREATE TABLE t1 (a INT UNSIGNED NOT NULL, b TIME); INSERT INTO t1 (a) VALUES (100000), (0), (100), (1000000),(10000), (1000), (10); UPDATE t1 SET b = SEC_TO_TIME(a); SELECT a, b FROM t1 ORDER BY b DESC; a b 1000000 277:46:40 100000 27:46:40 10000 02:46:40 1000 00:16:40 100 00:01:40 10 00:00:10 0 00:00:00 SELECT a, b FROM t1 ORDER BY SEC_TO_TIME(a) DESC; a b 1000000 277:46:40 100000 27:46:40 10000 02:46:40 1000 00:16:40 100 00:01:40 10 00:00:10 0 00:00:00 DROP TABLE t1; CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a), UNIQUE KEY b (b)); INSERT INTO t1 VALUES (1,1),(2,2); CREATE TABLE t2 (a INT, b INT, KEY a (a,b)); INSERT INTO t2 VALUES (1,1),(1,2),(2,1),(2,2); EXPLAIN SELECT 1 FROM t1,t2 WHERE t1.b=2 AND t1.a=t2.a ORDER BY t2.b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 const PRIMARY,b b 5 const 1 1 SIMPLE t2 ref a a 5 const 2 Using where; Using index DROP TABLE t1,t2; CREATE TABLE t1( id int auto_increment PRIMARY KEY, c2 int, c3 int, INDEX k2(c2), INDEX k3(c3)); INSERT INTO t1 (c2,c3) VALUES (31,34),(35,38),(34,31),(32,35),(31,39), (11,14),(15,18),(14,11),(12,15),(11,19); INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; INSERT INTO t1 (c2,c3) SELECT c2,c3 FROM t1; UPDATE t1 SET c2=20 WHERE id%100 = 0; SELECT COUNT(*) FROM t1; COUNT(*) 40960 CREATE TABLE t2 LIKE t1; INSERT INTO t2 SELECT * FROM t1 ORDER BY id; EXPLAIN SELECT id,c3 FROM t2 WHERE c2=11 ORDER BY c3 LIMIT 20; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 index k2 k3 5 NULL 111 Using where EXPLAIN SELECT id,c3 FROM t2 WHERE c2=11 ORDER BY c3 LIMIT 4000; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 index k2 k3 5 NULL 22318 Using where EXPLAIN SELECT id,c3 FROM t2 WHERE c2 BETWEEN 10 AND 12 ORDER BY c3 LIMIT 20; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 index k2 k3 5 NULL 73 Using where EXPLAIN SELECT id,c3 FROM t2 WHERE c2 BETWEEN 20 AND 30 ORDER BY c3 LIMIT 4000; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 range k2 k2 5 NULL 386 Using index condition; Using filesort SELECT id,c3 FROM t2 WHERE c2=11 ORDER BY c3 LIMIT 20; id c3 6 14 16 14 26 14 36 14 46 14 56 14 66 14 76 14 86 14 96 14 106 14 116 14 126 14 136 14 146 14 156 14 166 14 176 14 186 14 196 14 DROP TABLE t1,t2; CREATE TABLE t1 ( a INT, b INT, PRIMARY KEY (a), KEY ab(a, b) ); INSERT INTO t1 VALUES (1,1),(2,2),(3,3),(4,4); INSERT INTO t1 SELECT a + 4, b + 4 FROM t1; INSERT INTO t1 SELECT a + 8, b + 8 FROM t1; INSERT INTO t1 SELECT a +16, b +16 FROM t1; INSERT INTO t1 SELECT a +32, b +32 FROM t1; INSERT INTO t1 SELECT a +64, b +64 FROM t1; EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR GROUP BY (a, ab) GROUP BY a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL PRIMARY 4 NULL 128 Using index SELECT a FROM t1 IGNORE INDEX FOR GROUP BY (a, ab) GROUP BY a; a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 SELECT @tmp_tables_after = @tmp_tables_before ; @tmp_tables_after = @tmp_tables_before 1 EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR ORDER BY (a, ab) ORDER BY a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL PRIMARY 4 NULL 128 Using index SELECT a FROM t1 IGNORE INDEX FOR ORDER BY (a, ab) ORDER BY a; a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 SELECT @tmp_tables_after = @tmp_tables_before; @tmp_tables_after = @tmp_tables_before 1 DROP TABLE t1; # # Bug#31590: Wrong error message on sort buffer being too small. # create table t1(a int, b tinytext); insert into t1 values (1,2),(3,2); set session sort_buffer_size= 1000; Warnings: Warning 1292 Truncated incorrect sort_buffer_size value: '1000' set session max_sort_length= 2180; CALL mtr.add_suppression("Out of sort memory"); select * from t1 order by b; ERROR HY001: Out of sort memory, consider increasing server sort buffer size drop table t1; set session sort_buffer_size= 30000; # # Bug #39844: Query Crash Mysql Server 5.0.67 # CREATE TABLE t1 (a INT PRIMARY KEY); CREATE TABLE t2 (a INT PRIMARY KEY, b INT); CREATE TABLE t3 (c INT); INSERT INTO t1 (a) VALUES (1), (2); INSERT INTO t2 (a,b) VALUES (1,2), (2,3); INSERT INTO t3 (c) VALUES (1), (2); SELECT (SELECT t1.a FROM t1, t2 WHERE t1.a = t2.b AND t2.a = t3.c ORDER BY t1.a) FROM t3; (SELECT t1.a FROM t1, t2 WHERE t1.a = t2.b AND t2.a = t3.c ORDER BY t1.a) 2 NULL DROP TABLE t1, t2, t3; # # Bug #42760: Select doesn't return desired results when we have null # values # CREATE TABLE t1 ( a INT, c INT, UNIQUE KEY a_c (a,c), KEY (a)); INSERT INTO t1 VALUES (1, 10), (2, NULL); # Must use ref-or-null on the a_c index EXPLAIN SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref_or_null a_c,a a_c 10 const,const 2 Using where; Using index; Using filesort # Must return 1 row SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c; col 1 # Must use ref-or-null on the a_c index EXPLAIN SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c DESC; id select_type table type possible_keys key key_len ref rows Extra x x x ref_or_null a_c,a x x x x x # Must return 1 row SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c DESC; col 1 DROP TABLE t1; End of 5.0 tests CREATE TABLE t2 (a varchar(32), b int(11), c float, d double, UNIQUE KEY a (a,b,c), KEY b (b), KEY c (c)); CREATE TABLE t1 (a varchar(32), b char(3), UNIQUE KEY a (a,b), KEY b (b)); CREATE TABLE t3 (a varchar(32), b char(3), UNIQUE KEY a (a,b)); INSERT INTO t3 SELECT * FROM t1; EXPLAIN SELECT d FROM t1, t2 WHERE t2.b=14 AND t2.a=t1.a AND 5.110 ORDER BY f2, f0 LIMIT 20; f0 f1 f2 12 11 11 13 12 12 14 13 13 15 14 14 16 15 15 17 16 16 18 17 17 19 18 18 20 19 19 21 20 20 22 21 21 23 22 22 24 23 23 25 24 24 26 25 25 27 26 26 28 27 27 29 28 28 30 29 29 31 30 30 SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 0; f0 f1 f2 SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 10 OFFSET 10; f0 f1 f2 22 21 21 23 22 22 24 23 23 25 24 24 26 25 25 27 26 26 28 27 27 29 28 28 30 29 29 31 30 30 SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 0 OFFSET 10; f0 f1 f2 set sort_buffer_size= 32768; CREATE TEMPORARY TABLE tmp (f1 int, f2 varchar(20)); INSERT INTO tmp SELECT f1, f2 FROM t1; INSERT INTO t1(f1, f2) SELECT * FROM tmp; INSERT INTO tmp SELECT f1, f2 FROM t1; INSERT INTO t1(f1, f2) SELECT * FROM tmp; SELECT * FROM t1 ORDER BY f1 ASC, f0 LIMIT 30; f0 f1 f2 1 0 0 101 0 0 201 0 0 301 0 0 401 0 0 2 1 1 102 1 1 202 1 1 302 1 1 402 1 1 3 2 2 103 2 2 203 2 2 303 2 2 403 2 2 4 3 3 104 3 3 204 3 3 304 3 3 404 3 3 5 4 4 105 4 4 205 4 4 305 4 4 405 4 4 6 5 5 106 5 5 206 5 5 306 5 5 406 5 5 SELECT * FROM t1 ORDER BY f1 ASC, f0 LIMIT 0; f0 f1 f2 SELECT * FROM t1 ORDER BY f2 DESC, f0 LIMIT 30; f0 f1 f2 100 99 99 200 99 99 300 99 99 400 99 99 500 99 99 99 98 98 199 98 98 299 98 98 399 98 98 499 98 98 98 97 97 198 97 97 298 97 97 398 97 97 498 97 97 97 96 96 197 96 96 297 96 96 397 96 96 497 96 96 96 95 95 196 95 95 296 95 95 396 95 95 496 95 95 95 94 94 195 94 94 295 94 94 395 94 94 495 94 94 SELECT * FROM t1 ORDER BY f2 DESC, f0 LIMIT 0; f0 f1 f2 SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 20; f0 f1 f2 12 11 11 112 11 11 212 11 11 312 11 11 412 11 11 13 12 12 113 12 12 213 12 12 313 12 12 413 12 12 14 13 13 114 13 13 214 13 13 314 13 13 414 13 13 15 14 14 115 14 14 215 14 14 315 14 14 415 14 14 SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 0; f0 f1 f2 SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 10 OFFSET 10; f0 f1 f2 14 13 13 114 13 13 214 13 13 314 13 13 414 13 13 15 14 14 115 14 14 215 14 14 315 14 14 415 14 14 SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 0 OFFSET 10; f0 f1 f2 set sort_buffer_size= 32768; SELECT SQL_CALC_FOUND_ROWS * FROM t1 ORDER BY f1, f0 LIMIT 30; f0 f1 f2 1 0 0 101 0 0 201 0 0 301 0 0 401 0 0 2 1 1 102 1 1 202 1 1 302 1 1 402 1 1 3 2 2 103 2 2 203 2 2 303 2 2 403 2 2 4 3 3 104 3 3 204 3 3 304 3 3 404 3 3 5 4 4 105 4 4 205 4 4 305 4 4 405 4 4 6 5 5 106 5 5 206 5 5 306 5 5 406 5 5 SELECT FOUND_ROWS(); FOUND_ROWS() 500 SELECT SQL_CALC_FOUND_ROWS * FROM t1 ORDER BY f1, f0 LIMIT 0; f0 f1 f2 SELECT FOUND_ROWS(); FOUND_ROWS() 500 SELECT SQL_CALC_FOUND_ROWS * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 20; f0 f1 f2 12 11 11 112 11 11 212 11 11 312 11 11 412 11 11 13 12 12 113 12 12 213 12 12 313 12 12 413 12 12 14 13 13 114 13 13 214 13 13 314 13 13 414 13 13 15 14 14 115 14 14 215 14 14 315 14 14 415 14 14 SELECT FOUND_ROWS(); FOUND_ROWS() 445 SELECT SQL_CALC_FOUND_ROWS * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 0; f0 f1 f2 SELECT FOUND_ROWS(); FOUND_ROWS() 445 SELECT SQL_CALC_FOUND_ROWS * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 10 OFFSET 10; f0 f1 f2 14 13 13 114 13 13 214 13 13 314 13 13 414 13 13 15 14 14 115 14 14 215 14 14 315 14 14 415 14 14 SELECT FOUND_ROWS(); FOUND_ROWS() 445 SELECT SQL_CALC_FOUND_ROWS * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 0 OFFSET 10; f0 f1 f2 SELECT FOUND_ROWS(); FOUND_ROWS() 445 set sort_buffer_size= 327680; SELECT * FROM t1 JOIN tmp on t1.f2=tmp.f2 ORDER BY tmp.f1, f0 LIMIT 30; f0 f1 f2 f1 f2 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 101 0 0 0 0 101 0 0 0 0 101 0 0 0 0 201 0 0 0 0 201 0 0 0 0 201 0 0 0 0 301 0 0 0 0 301 0 0 0 0 301 0 0 0 0 401 0 0 0 0 401 0 0 0 0 401 0 0 0 0 2 1 1 1 1 2 1 1 1 1 2 1 1 1 1 102 1 1 1 1 102 1 1 1 1 102 1 1 1 1 202 1 1 1 1 202 1 1 1 1 202 1 1 1 1 302 1 1 1 1 302 1 1 1 1 302 1 1 1 1 402 1 1 1 1 402 1 1 1 1 402 1 1 1 1 SELECT * FROM t1 JOIN tmp on t1.f2=tmp.f2 ORDER BY tmp.f1, f0 LIMIT 30 OFFSET 30; f0 f1 f2 f1 f2 3 2 2 2 2 3 2 2 2 2 3 2 2 2 2 103 2 2 2 2 103 2 2 2 2 103 2 2 2 2 203 2 2 2 2 203 2 2 2 2 203 2 2 2 2 303 2 2 2 2 303 2 2 2 2 303 2 2 2 2 403 2 2 2 2 403 2 2 2 2 403 2 2 2 2 4 3 3 3 3 4 3 3 3 3 4 3 3 3 3 104 3 3 3 3 104 3 3 3 3 104 3 3 3 3 204 3 3 3 3 204 3 3 3 3 204 3 3 3 3 304 3 3 3 3 304 3 3 3 3 304 3 3 3 3 404 3 3 3 3 404 3 3 3 3 404 3 3 3 3 SELECT SQL_CALC_FOUND_ROWS * FROM t1 JOIN tmp on t1.f2=tmp.f2 ORDER BY tmp.f1, f0 LIMIT 30 OFFSET 30; f0 f1 f2 f1 f2 3 2 2 2 2 3 2 2 2 2 3 2 2 2 2 103 2 2 2 2 103 2 2 2 2 103 2 2 2 2 203 2 2 2 2 203 2 2 2 2 203 2 2 2 2 303 2 2 2 2 303 2 2 2 2 303 2 2 2 2 403 2 2 2 2 403 2 2 2 2 403 2 2 2 2 4 3 3 3 3 4 3 3 3 3 4 3 3 3 3 104 3 3 3 3 104 3 3 3 3 104 3 3 3 3 204 3 3 3 3 204 3 3 3 3 204 3 3 3 3 304 3 3 3 3 304 3 3 3 3 304 3 3 3 3 404 3 3 3 3 404 3 3 3 3 404 3 3 3 3 SELECT FOUND_ROWS(); FOUND_ROWS() 1500 SELECT SQL_CALC_FOUND_ROWS * FROM t1 JOIN tmp on t1.f2=tmp.f2 WHERE t1.f2>20 ORDER BY tmp.f1, f0 LIMIT 30 OFFSET 30; f0 f1 f2 f1 f2 24 23 23 23 23 24 23 23 23 23 24 23 23 23 23 124 23 23 23 23 124 23 23 23 23 124 23 23 23 23 224 23 23 23 23 224 23 23 23 23 224 23 23 23 23 324 23 23 23 23 324 23 23 23 23 324 23 23 23 23 424 23 23 23 23 424 23 23 23 23 424 23 23 23 23 25 24 24 24 24 25 24 24 24 24 25 24 24 24 24 125 24 24 24 24 125 24 24 24 24 125 24 24 24 24 225 24 24 24 24 225 24 24 24 24 225 24 24 24 24 325 24 24 24 24 325 24 24 24 24 325 24 24 24 24 425 24 24 24 24 425 24 24 24 24 425 24 24 24 24 SELECT FOUND_ROWS(); FOUND_ROWS() 1185 CREATE VIEW v1 as SELECT * FROM t1 ORDER BY f1, f0 LIMIT 30; SELECT * FROM v1; f0 f1 f2 1 0 0 101 0 0 201 0 0 301 0 0 401 0 0 2 1 1 102 1 1 202 1 1 302 1 1 402 1 1 3 2 2 103 2 2 203 2 2 303 2 2 403 2 2 4 3 3 104 3 3 204 3 3 304 3 3 404 3 3 5 4 4 105 4 4 205 4 4 305 4 4 405 4 4 6 5 5 106 5 5 206 5 5 306 5 5 406 5 5 drop view v1; CREATE VIEW v1 as SELECT * FROM t1 ORDER BY f1, f0 LIMIT 100; SELECT * FROM v1 ORDER BY f2, f0 LIMIT 30; f0 f1 f2 1 0 0 101 0 0 201 0 0 301 0 0 401 0 0 2 1 1 102 1 1 202 1 1 302 1 1 402 1 1 11 10 10 111 10 10 211 10 10 311 10 10 411 10 10 12 11 11 112 11 11 212 11 11 312 11 11 412 11 11 13 12 12 113 12 12 213 12 12 313 12 12 413 12 12 14 13 13 114 13 13 214 13 13 314 13 13 414 13 13 CREATE VIEW v2 as SELECT * FROM t1 ORDER BY f2, f0 LIMIT 100; SELECT * FROM v1 JOIN v2 on v1.f1=v2.f1 ORDER BY v1.f2,v1.f0,v2.f0 LIMIT 30; f0 f1 f2 f0 f1 f2 1 0 0 1 0 0 1 0 0 101 0 0 1 0 0 201 0 0 1 0 0 301 0 0 1 0 0 401 0 0 101 0 0 1 0 0 101 0 0 101 0 0 101 0 0 201 0 0 101 0 0 301 0 0 101 0 0 401 0 0 201 0 0 1 0 0 201 0 0 101 0 0 201 0 0 201 0 0 201 0 0 301 0 0 201 0 0 401 0 0 301 0 0 1 0 0 301 0 0 101 0 0 301 0 0 201 0 0 301 0 0 301 0 0 301 0 0 401 0 0 401 0 0 1 0 0 401 0 0 101 0 0 401 0 0 201 0 0 401 0 0 301 0 0 401 0 0 401 0 0 2 1 1 2 1 1 2 1 1 102 1 1 2 1 1 202 1 1 2 1 1 302 1 1 2 1 1 402 1 1 SELECT floor(f1/10) f3, count(f2) FROM t1 GROUP BY 1 ORDER BY 2,1 LIMIT 5; f3 count(f2) 0 50 1 50 2 50 3 50 4 50 SELECT floor(f1/10) f3, count(f2) FROM t1 GROUP BY 1 ORDER BY 2,1 LIMIT 0; f3 count(f2) CREATE PROCEDURE wl1393_sp_test() BEGIN SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 30; SELECT * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 15 OFFSET 15; SELECT SQL_CALC_FOUND_ROWS * FROM t1 WHERE f1>10 ORDER BY f2, f0 LIMIT 15 OFFSET 15; SELECT FOUND_ROWS(); SELECT * FROM v1 ORDER BY f2, f0 LIMIT 30; END| CALL wl1393_sp_test()| f0 f1 f2 12 11 11 112 11 11 212 11 11 312 11 11 412 11 11 13 12 12 113 12 12 213 12 12 313 12 12 413 12 12 14 13 13 114 13 13 214 13 13 314 13 13 414 13 13 15 14 14 115 14 14 215 14 14 315 14 14 415 14 14 16 15 15 116 15 15 216 15 15 316 15 15 416 15 15 17 16 16 117 16 16 217 16 16 317 16 16 417 16 16 f0 f1 f2 15 14 14 115 14 14 215 14 14 315 14 14 415 14 14 16 15 15 116 15 15 216 15 15 316 15 15 416 15 15 17 16 16 117 16 16 217 16 16 317 16 16 417 16 16 f0 f1 f2 15 14 14 115 14 14 215 14 14 315 14 14 415 14 14 16 15 15 116 15 15 216 15 15 316 15 15 416 15 15 17 16 16 117 16 16 217 16 16 317 16 16 417 16 16 FOUND_ROWS() 445 f0 f1 f2 1 0 0 101 0 0 201 0 0 301 0 0 401 0 0 2 1 1 102 1 1 202 1 1 302 1 1 402 1 1 11 10 10 111 10 10 211 10 10 311 10 10 411 10 10 12 11 11 112 11 11 212 11 11 312 11 11 412 11 11 13 12 12 113 12 12 213 12 12 313 12 12 413 12 12 14 13 13 114 13 13 214 13 13 314 13 13 414 13 13 DROP PROCEDURE wl1393_sp_test| SELECT d1.f1, d1.f2 FROM t1 LEFT JOIN (SELECT * FROM t1 ORDER BY f1 LIMIT 30) d1 on t1.f1=d1.f1 ORDER BY d1.f2 DESC LIMIT 30; f1 f2 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 SELECT * FROM t1 WHERE f1 = (SELECT f1 FROM t1 ORDER BY 1 LIMIT 1); f0 f1 f2 1 0 0 101 0 0 201 0 0 301 0 0 401 0 0 SELECT * FROM t1 WHERE f1 = (SELECT f1 FROM t1 ORDER BY 1 LIMIT 2); ERROR 21000: Subquery returns more than 1 row DROP TABLE t1, tmp; DROP VIEW v1, v2; # end of WL#1393 - Optimizing filesort with small limit # # Bug #58761 # Crash in Field::is_null in field.h on subquery in WHERE clause # CREATE TABLE t1 ( pk INT NOT NULL AUTO_INCREMENT, col_int_key INT DEFAULT NULL, col_varchar_key VARCHAR(1) DEFAULT NULL, PRIMARY KEY (pk), KEY col_varchar_key (col_varchar_key,col_int_key) ); INSERT INTO t1 VALUES (27,7,'x'); INSERT INTO t1 VALUES (28,6,'m'); INSERT INTO t1 VALUES (29,4,'c'); CREATE TABLE where_subselect SELECT DISTINCT `pk` AS field1 , `pk` AS field2 FROM t1 AS alias1 WHERE alias1 . `col_int_key` > 229 OR alias1 . `col_varchar_key` IS NOT NULL GROUP BY field1, field2 ; SELECT * FROM where_subselect WHERE (field1, field2) IN ( SELECT DISTINCT `pk` AS field1 , `pk` AS field2 FROM t1 AS alias1 WHERE alias1 . `col_int_key` > 229 OR alias1 . `col_varchar_key` IS NOT NULL GROUP BY field1, field2 ); field1 field2 27 27 28 28 29 29 DROP TABLE t1; DROP TABLE where_subselect; # End of Bug #58761 CREATE TABLE t1 ( id1 INT NULL, id2 INT NOT NULL, junk INT NOT NULL, PRIMARY KEY (id1, id2, junk), INDEX id2_j_id1 (id2, junk, id1) ); INSERT INTO t1 VALUES (1, 1, 1), (2, 1, 2), (3, 1, 3), (4, 1, 4); INSERT INTO t1 VALUES (5, 2, 1), (6, 2, 2), (7, 2, 3), (8, 2, 4); INSERT INTO t1 VALUES (9, 3, 1), (10, 3, 2), (11, 3, 3), (12, 3, 4); INSERT INTO t1 VALUES (13, 4, 1), (14, 4, 2), (15, 4, 3), (16, 4, 4); INSERT INTO t1 VALUES (17, 5, 1), (18, 5, 2), (19, 5, 3), (20, 5, 4); INSERT INTO t1 VALUES (21, 6, 1), (22, 6, 2), (23, 6, 3), (24, 6, 4); INSERT INTO t1 VALUES (25, 7, 1), (26, 7, 2), (27, 7, 3), (28, 7, 4); INSERT INTO t1 VALUES (29, 8, 1), (30, 8, 2), (31, 8, 3), (32, 8, 4); INSERT INTO t1 VALUES (33, 9, 1), (34, 9, 2), (35, 9, 3), (36, 9, 4); EXPLAIN SELECT id1 FROM t1 WHERE id2 = 4 ORDER BY id1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref id2_j_id1 id2_j_id1 4 const 4 Using where; Using index; Using filesort SELECT id1 FROM t1 WHERE id2 = 4 ORDER BY id1; id1 13 14 15 16 DROP TABLE t1; CREATE TABLE t1 ( a INT, b INT NOT NULL, c char(100), KEY (b, c), KEY (b, a, c) ) DEFAULT CHARSET = utf8; INSERT INTO t1 VALUES (1, 1, 1), (2, 2, 2), (3, 3, 3), (4, 4, 4), (5, 5, 5), (6, 6, 6), (7, 7, 7), (8, 8, 8), (9, 9, 9); INSERT INTO t1 SELECT a + 10, b, c FROM t1; INSERT INTO t1 SELECT a + 20, b, c FROM t1; INSERT INTO t1 SELECT a + 40, b, c FROM t1; INSERT INTO t1 SELECT a + 80, b, c FROM t1; INSERT INTO t1 SELECT a + 160, b, c FROM t1; INSERT INTO t1 SELECT a + 320, b, c FROM t1; INSERT INTO t1 SELECT a + 640, b, c FROM t1; INSERT INTO t1 SELECT a + 1280, b, c FROM t1 LIMIT 80; EXPLAIN SELECT a FROM t1 WHERE b = 1 ORDER BY c DESC LIMIT 9; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range b,b_2 b 4 NULL 226 Using where SELECT a FROM t1 WHERE b = 1 ORDER BY c DESC LIMIT 9; a 2071 2061 2051 2041 2031 2021 2011 2001 1991 EXPLAIN SELECT DISTINCT a FROM t1 WHERE b = 1 ORDER BY c DESC LIMIT 0, 9; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range b,b_2 b 4 NULL 226 Using where; Using temporary SELECT DISTINCT a FROM t1 WHERE b = 1 ORDER BY c DESC LIMIT 0, 9; a 2071 2061 2051 2041 2031 2021 2011 2001 1991 DROP TABLE t1; # # Bug #43029: FORCE INDEX FOR ORDER BY is ignored when join buffering # is used # CREATE TABLE t1 (a INT, b INT, KEY (a)); INSERT INTO t1 VALUES (0, NULL), (1, NULL), (2, NULL), (3, NULL); INSERT INTO t1 SELECT a+4, b FROM t1; INSERT INTO t1 SELECT a+8, b FROM t1; CREATE TABLE t2 (a INT, b INT); INSERT INTO t2 VALUES (0,NULL), (1,NULL), (2,NULL), (3,NULL), (4,NULL); INSERT INTO t2 SELECT a+4, b FROM t2; # shouldn't have "using filesort" EXPLAIN SELECT * FROM t1 FORCE INDEX FOR ORDER BY (a), t2 WHERE t1.a < 2 ORDER BY t1.a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 5 NULL 2 Using index condition; Using temporary; Using filesort 1 SIMPLE t2 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join) # should have "using filesort" EXPLAIN SELECT * FROM t1 USE INDEX FOR ORDER BY (a), t2 WHERE t1.a < 2 ORDER BY t1.a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 5 NULL 2 Using index condition; Using temporary; Using filesort 1 SIMPLE t2 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join) # should have "using filesort" EXPLAIN SELECT * FROM t1 FORCE INDEX FOR JOIN (a), t2 WHERE t1.a < 2 ORDER BY t1.a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 5 NULL 2 Using index condition; Using temporary; Using filesort 1 SIMPLE t2 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join) DROP TABLE t1, t2; # # Bug #50394: Regression in EXPLAIN with index scan, LIMIT, GROUP BY and # ORDER BY computed col # CREATE TABLE t1 ( a INT NOT NULL, b INT NOT NULL, KEY( a, b ) ); INSERT INTO t1 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5); INSERT INTO t1 SELECT a + 5, b + 5 FROM t1; CREATE TABLE t2( a INT PRIMARY KEY, b INT ); INSERT INTO t2 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5); INSERT INTO t2 SELECT a + 5, b + 5 FROM t2; EXPLAIN SELECT count(*) AS c, t1.a FROM t1 JOIN t2 ON t1.b = t2.a WHERE t2.b = 1 GROUP BY t1.a ORDER by c LIMIT 2; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL a 8 NULL 10 Using index; Using temporary; Using filesort 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 Using where DROP TABLE t1, t2; # # Bug #707848: WHERE condition with OR + ORDER BY + field substitution # CREATE TABLE t1 (a int PRIMARY KEY); INSERT INTO t1 VALUES (9), (7), (11), (15), (2), (4), (1), (5), (14), (54), (3), (8); EXPLAIN EXTENDED SELECT * FROM t1 r JOIN t1 s ON r.a = s.a WHERE s.a IN (2,9) OR s.a < 100 AND s.a != 0 ORDER BY 1 LIMIT 10; id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE r range PRIMARY PRIMARY 4 NULL 12 100.00 Using where; Using index 1 SIMPLE s eq_ref PRIMARY PRIMARY 4 test.r.a 1 100.00 Using index Warnings: Note 1003 select `test`.`r`.`a` AS `a`,`test`.`s`.`a` AS `a` from `test`.`t1` `r` join `test`.`t1` `s` where `test`.`s`.`a` = `test`.`r`.`a` and (`test`.`r`.`a` in (2,9) or `test`.`r`.`a` < 100 and `test`.`r`.`a` <> 0) order by 1 limit 10 SELECT * FROM t1 r JOIN t1 s ON r.a = s.a WHERE s.a IN (2,9) OR s.a < 100 AND s.a != 0 ORDER BY 1 LIMIT 10; a a 1 1 2 2 3 3 4 4 5 5 7 7 8 8 9 9 11 11 14 14 DROP TABLE t1; # # Bug #59110: Memory leak of QUICK_SELECT_I allocated memory # and # Bug #59308: Incorrect result for SELECT DISTINCT ... ORDER BY DESC # Use Valgrind to detect #59110! # CREATE TABLE t1 (a INT,KEY (a)); INSERT INTO t1 VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9),(10); EXPLAIN SELECT DISTINCT a,1 FROM t1 WHERE a <> 1 ORDER BY a DESC; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 5 NULL 10 Using where; Using index SELECT DISTINCT a,1 FROM t1 WHERE a <> 1 ORDER BY a DESC; a 1 10 1 9 1 8 1 7 1 6 1 5 1 4 1 3 1 2 1 DROP TABLE t1; # # Bug#11765255 58201: # VALGRIND/CRASH WHEN ORDERING BY MULTIPLE AGGREGATE FUNCTIONS # select 1 order by max(1) + min(1); 1 1 End of 5.1 tests # # Bug #38745: MySQL 5.1 optimizer uses filesort for ORDER BY # when it should use index # CREATE TABLE t1 (i1 integer NOT NULL PRIMARY KEY); CREATE TABLE t2 (i2 integer NOT NULL PRIMARY KEY); CREATE TABLE t3 (i3 integer); INSERT INTO t1 VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12); INSERT INTO t2 SELECT * FROM t1; EXPLAIN EXTENDED SELECT t1.*, t2.* FROM t1 JOIN t2 ON t1.i1 = t2.i2 LEFT JOIN t3 ON t2.i2 = t3.i3 ORDER BY t1.i1 LIMIT 5; id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t3 system NULL NULL NULL NULL 0 0.00 Const row not found 1 SIMPLE t1 index PRIMARY PRIMARY 4 NULL 5 100.00 Using index 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.i1 1 100.00 Using index Warnings: Note 1003 select `test`.`t1`.`i1` AS `i1`,`test`.`t2`.`i2` AS `i2` from `test`.`t1` join `test`.`t2` where `test`.`t2`.`i2` = `test`.`t1`.`i1` order by `test`.`t1`.`i1` limit 5 SELECT t1.*, t2.* FROM t1 JOIN t2 ON t1.i1 = t2.i2 LEFT JOIN t3 ON t2.i2 = t3.i3 ORDER BY t1.i1 LIMIT 5; i1 i2 1 1 2 2 3 3 4 4 5 5 DROP TABLE t1, t2, t3; # # Fix of LP BUG#793589 Wrong result with double ORDER BY # CREATE TABLE t1 ( b int) ; INSERT INTO t1 VALUES (8),(9); CREATE TABLE t2 ( a int, b int, PRIMARY KEY (a)) ; INSERT INTO t2 VALUES (6,7),(7,7),(8,1),(9,7),(10,1),(11,5),(12,2),(13,0),(14,1),(15,8),(16,1),(17,1),(18,9),(19,1),(20,5); SELECT t2.b AS field1 FROM t1, t2 WHERE t1.b = t2.a GROUP BY field1 ORDER BY t1.b, field1; field1 1 7 SELECT t2.b, t1.b FROM t1, t2 WHERE t1.b = t2.a GROUP BY t2.b ORDER BY t1.b, t2.b; b b 1 8 7 9 SELECT t2.b,t1.b FROM t1, t2 WHERE t1.b = t2.a GROUP BY t2.b ORDER BY t1.b; b b 1 8 7 9 SELECT t2.b FROM t1, t2 WHERE t1.b = t2.a GROUP BY t2.b ORDER BY t1.b; b 1 7 # field1 removed from ORDER BY explain extended SELECT t2.b AS field1 FROM t1, t2 WHERE t1.b = t2.a GROUP BY field1 ORDER BY t1.b, field1; id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 2 100.00 Using where; Using temporary; Using filesort 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 100.00 Warnings: Note 1003 select `test`.`t2`.`b` AS `field1` from `test`.`t1` join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`b` group by `test`.`t2`.`b` order by `test`.`t1`.`b` explain extended SELECT t2.b, t1.b FROM t1, t2 WHERE t1.b = t2.a GROUP BY t2.b ORDER BY t1.b, t2.b; id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 2 100.00 Using where; Using temporary; Using filesort 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 100.00 Warnings: Note 1003 select `test`.`t2`.`b` AS `b`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`b` group by `test`.`t2`.`b` order by `test`.`t1`.`b` explain extended SELECT t2.b,t1.b FROM t1, t2 WHERE t1.b = t2.a GROUP BY t2.b ORDER BY t1.b; id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 2 100.00 Using where; Using temporary; Using filesort 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 100.00 Warnings: Note 1003 select `test`.`t2`.`b` AS `b`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`b` group by `test`.`t2`.`b` order by `test`.`t1`.`b` explain extended SELECT t2.b FROM t1, t2 WHERE t1.b = t2.a GROUP BY t2.b ORDER BY t1.b; id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 2 100.00 Using where; Using temporary; Using filesort 1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 100.00 Warnings: Note 1003 select `test`.`t2`.`b` AS `b` from `test`.`t1` join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`b` group by `test`.`t2`.`b` order by `test`.`t1`.`b` drop table t1,t2; End of 5.2 tests # # Bug mdev-449: ORDER BY with small sort_buffer_size # CREATE TABLE t1(f0 int auto_increment primary key, f1 int, f2 varchar(200)); INSERT INTO t1(f1, f2) VALUES (0,"0"),(1,"1"),(2,"2"),(3,"3"),(4,"4"),(5,"5"), (6,"6"),(7,"7"),(8,"8"),(9,"9"),(10,"10"), (11,"11"),(12,"12"),(13,"13"),(14,"14"),(15,"15"), (16,"16"),(17,"17"),(18,"18"),(19,"19"),(20,"20"), (21,"21"),(22,"22"),(23,"23"),(24,"24"),(25,"25"), (26,"26"),(27,"27"),(28,"28"),(29,"29"),(30,"30"), (31,"31"),(32,"32"),(33,"33"),(34,"34"),(35,"35"), (36,"36"),(37,"37"),(38,"38"),(39,"39"),(40,"40"), (41,"41"),(42,"42"),(43,"43"),(44,"44"),(45,"45"), (46,"46"),(47,"47"),(48,"48"),(49,"49"),(50,"50"), (51,"51"),(52,"52"),(53,"53"),(54,"54"),(55,"55"), (56,"56"),(57,"57"),(58,"58"),(59,"59"),(60,"60"), (61,"61"),(62,"62"),(63,"63"),(64,"64"),(65,"65"), (66,"66"),(67,"67"),(68,"68"),(69,"69"),(70,"70"), (71,"71"),(72,"72"),(73,"73"),(74,"74"),(75,"75"), (76,"76"),(77,"77"),(78,"78"),(79,"79"),(80,"80"), (81,"81"),(82,"82"),(83,"83"),(84,"84"),(85,"85"), (86,"86"),(87,"87"),(88,"88"),(89,"89"),(90,"90"), (91,"91"),(92,"92"),(93,"93"),(94,"94"),(95,"95"), (96,"96"),(97,"97"),(98,"98"),(99,"99"); set @save_sort_buffer_size= @@sort_buffer_size; set sort_buffer_size= 2000; SELECT * FROM t1 ORDER BY f1 DESC, f0; f0 f1 f2 100 99 99 99 98 98 98 97 97 97 96 96 96 95 95 95 94 94 94 93 93 93 92 92 92 91 91 91 90 90 90 89 89 89 88 88 88 87 87 87 86 86 86 85 85 85 84 84 84 83 83 83 82 82 82 81 81 81 80 80 80 79 79 79 78 78 78 77 77 77 76 76 76 75 75 75 74 74 74 73 73 73 72 72 72 71 71 71 70 70 70 69 69 69 68 68 68 67 67 67 66 66 66 65 65 65 64 64 64 63 63 63 62 62 62 61 61 61 60 60 60 59 59 59 58 58 58 57 57 57 56 56 56 55 55 55 54 54 54 53 53 53 52 52 52 51 51 51 50 50 50 49 49 49 48 48 48 47 47 47 46 46 46 45 45 45 44 44 44 43 43 43 42 42 42 41 41 41 40 40 40 39 39 39 38 38 38 37 37 37 36 36 36 35 35 35 34 34 34 33 33 33 32 32 32 31 31 31 30 30 30 29 29 29 28 28 28 27 27 27 26 26 26 25 25 25 24 24 24 23 23 23 22 22 22 21 21 21 20 20 20 19 19 19 18 18 18 17 17 17 16 16 16 15 15 15 14 14 14 13 13 13 12 12 12 11 11 11 10 10 10 9 9 9 8 8 8 7 7 7 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 set sort_buffer_size= @save_sort_buffer_size; DROP TABLE t1; End of 5.3 tests # # Bug 54599: discarded fast range scan for query with # GROUP BY + ORDER BY + LIMIT # create table t0 (a int); insert into t0 values (0), (1), (2), (3), (4), (5), (6), (7), (8), (9); create table t1 (a int, b int, index idx1(a,b), index idx2(b,a)); insert into t1 select 1000*s4.a+100*s3.a+10*s2.a + s1.a, 1000*s4.a+100*s3.a+10*s2.a+s1.a from t0 s1, t0 s2, t0 s3, t0 s4; analyze table t1; explain select b, count(*) num_cnt from t1 where a > 9750 group by b order by num_cnt; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range idx1 idx1 5 NULL 503 Using where; Using index; Using temporary; Using filesort flush status; select b, count(*) num_cnt from t1 where a > 9750 group by b order by num_cnt; show status like '%Handler_read%'; Variable_name Value Handler_read_first 0 Handler_read_key 250 Handler_read_last 0 Handler_read_next 249 Handler_read_prev 0 Handler_read_retry 0 Handler_read_rnd 249 Handler_read_rnd_deleted 0 Handler_read_rnd_next 250 explain select b, count(*) num_cnt from t1 where a > 9750 group by b order by num_cnt limit 1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range idx1 idx1 5 NULL 503 Using where; Using index; Using temporary; Using filesort flush status; select b, count(*) num_cnt from t1 where a > 9750 group by b order by num_cnt limit 1; show status like '%Handler_read%'; Variable_name Value Handler_read_first 0 Handler_read_key 250 Handler_read_last 0 Handler_read_next 249 Handler_read_prev 0 Handler_read_retry 0 Handler_read_rnd 1 Handler_read_rnd_deleted 0 Handler_read_rnd_next 250 drop table t0, t1; # # LP bug #1002508 : the number of expected rows to be examined is off # (bug #13528826) # CREATE TABLE t1(a int PRIMARY KEY, b int) ENGINE=myisam; INSERT INTO t1 VALUES (5, 10), (2, 70), (7, 80), (6, 20), (1, 50), (9, 40), (8, 30), (3, 60); CREATE TABLE t2 (p int, a int, INDEX i_a(a)) ENGINE=myisam; INSERT INTO t2 VALUES (103, 7), (109, 3), (102, 3), (108, 1), (106, 3), (107, 7), (105, 1), (101, 3), (100, 7), (110, 1); EXPLAIN SELECT t1.a FROM t1 LEFT JOIN t2 ON t1.a=t2.a ORDER BY t1.a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL PRIMARY 4 NULL 8 Using index 1 SIMPLE t2 ref i_a i_a 5 test.t1.a 2 Using index EXPLAIN SELECT t1.a FROM t1 LEFT JOIN t2 ON t1.a=t2.a ORDER BY t1.a LIMIT 8; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL PRIMARY 4 NULL 4 Using index 1 SIMPLE t2 ref i_a i_a 5 test.t1.a 2 Using index EXPLAIN SELECT t1.a FROM t1 LEFT JOIN t2 ON t1.a=t2.a ORDER BY t1.a LIMIT 100; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL PRIMARY 4 NULL 8 Using index 1 SIMPLE t2 ref i_a i_a 5 test.t1.a 2 Using index DROP TABLE t1,t2; # # MDEV-4974 memory leak in 5.5.32-MariaDB-1~wheezy-log # set sort_buffer_size=default; set max_sort_length=default; create table t1(a int); insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); create table t2 (b int, col1 varchar(255), col2 varchar(255) ) character set utf8; insert into t2 select A.a+10*B.a, concat('wow-wow-col1-value-', A.a+10*B.a+100*C.a), concat('wow-wow-col2-value-', A.a+10*B.a+100*C.a) from t1 A, t1 B, t1 C where C.a < 8; create table t3 as select distinct A.col1 as XX, B.col1 as YY from t2 A, t2 B where A.b = B.b order by A.col2, B.col2 limit 10, 1000000; drop table t1,t2,t3; # # mdev-10705 : long order by list that can be skipped # SELECT 1 UNION ( SELECT 2 ORDER BY NULL, @a0 := 3, @a1 := 3, @a2 := 3, @a3 := 3, @a4 := 3, @a5 := 3, @a6 := 3, @a7 := 3, @a8 := 3, @a9 := 3, @a10 := 3 ); 1 1 2 # # mdev-6706: semi-join with duplicate weedout + ORDER BY # CREATE TABLE t1 (f1 VARCHAR(3)) ENGINE=MyISAM; INSERT INTO t1 VALUES ('foo'); CREATE TABLE t2 (f2 VARCHAR(3)) ENGINE=MyISAM; INSERT INTO t2 VALUES ('bar'),('baz'); CREATE TABLE t3 (i3_key INT, f3_key VARCHAR(3), f3 VARCHAR(3), KEY(f3_key,i3_key)) ENGINE=MyISAM; INSERT INTO t3 VALUES (0,'qux','qux'),(8,'bar','bar'); SELECT CONCAT( f1, f2 ) AS field FROM t1, t2 WHERE f1 = ANY ( SELECT f1 FROM t1 LEFT JOIN ( t3 AS t3a, t3 AS t3b ) ON ( t3b.f3_key = t3a.f3 ) WHERE t3a.f3 < f1 OR t3b.f3 != f1 ); field foobar foobaz SELECT CONCAT( f1, f2 ) AS field FROM t1, t2 WHERE f1 = ANY ( SELECT f1 FROM t1 LEFT JOIN ( t3 AS t3a, t3 AS t3b ) ON ( t3b.f3_key = t3a.f3 ) WHERE t3a.f3 < f1 OR t3b.f3 != f1 ) ORDER BY field; field foobar foobaz EXPLAIN EXTENDED SELECT CONCAT( f1, f2 ) AS field FROM t1, t2 WHERE f1 = ANY ( SELECT f1 FROM t1 LEFT JOIN ( t3 AS t3a, t3 AS t3b ) ON ( t3b.f3_key = t3a.f3 ) WHERE t3a.f3 < f1 OR t3b.f3 != f1 ) ORDER BY field; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t1 system NULL NULL NULL NULL 1 100.00 Using temporary; Using filesort 1 PRIMARY t1 system NULL NULL NULL NULL 1 100.00 1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00 1 PRIMARY t3a ALL NULL NULL NULL NULL 2 100.00 Using where; Start temporary 1 PRIMARY t3b ref f3_key f3_key 6 test.t3a.f3 1 100.00 Using where; End temporary Warnings: Note 1003 select concat('foo',`test`.`t2`.`f2`) AS `field` from `test`.`t2` semi join ((`test`.`t3` `t3a` join `test`.`t3` `t3b`)) where `test`.`t3a`.`f3` < 'foo' or `test`.`t3b`.`f3` <> 'foo' order by concat('foo',`test`.`t2`.`f2`) DROP TABLE t1,t2,t3; End of 5.5 tests # # MDEV-5884: EXPLAIN UPDATE ... ORDER BY LIMIT shows wrong #rows # create table t2(a int); insert into t2 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); create table t1 (key1 int, col1 int, key(key1)); insert into t1 select A.a + 10 * B.a + 100 * C.a, 1234 from t2 A, t2 B, t2 C; # Should show rows=2, not rows=100 explain update t1 set key1=key1+1 where key1 between 10 and 110 order by key1 limit 2; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range key1 key1 5 NULL 2 Using where; Using buffer drop table t1,t2; # # MDEV-465: Optimizer : wrong index choice, leading to strong performances issues # CREATE TABLE t1 ( id1 int(10) unsigned NOT NULL auto_increment, id2 tinyint(3) unsigned NOT NULL default '0', id3 tinyint(3) unsigned NOT NULL default '0', id4 int(10) unsigned NOT NULL default '0', date timestamp NOT NULL default CURRENT_TIMESTAMP, PRIMARY KEY (id1), KEY id_234_date (id2,id3,id4,date), KEY id_23_date (id2,id3,date) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; # t1 has "bad" index declaration order.. CREATE TABLE t2 ( id1 int(10) unsigned NOT NULL auto_increment, id2 tinyint(3) unsigned NOT NULL default '0', id3 tinyint(3) unsigned NOT NULL default '0', id4 int(10) unsigned NOT NULL default '0', date timestamp NOT NULL default CURRENT_TIMESTAMP, PRIMARY KEY (id1), KEY id_23_date (id2,id3,date), KEY id_234_date (id2,id3,id4,date) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; # t2 has a "good" index declaration order INSERT INTO t1 (id2,id3,id4) VALUES (1,1,1),(1,1,1),(1,1,1),(1,1,1),(1,0,1),(1,2,1),(1,3,1); INSERT INTO t1 (id2,id3,id4) VALUES (1,1,1),(1,1,1),(1,1,1),(1,1,1),(1,0,1),(1,2,1),(1,3,1); INSERT INTO t2 (id2,id3,id4) VALUES (1,1,1),(1,1,1),(1,1,1),(1,1,1),(1,0,1),(1,2,1),(1,3,1); INSERT INTO t2 (id2,id3,id4) VALUES (1,1,1),(1,1,1),(1,1,1),(1,1,1),(1,0,1),(1,2,1),(1,3,1); # The following two must both use id_23_date and no "using filesort": EXPLAIN SELECT id1 FROM t1 WHERE id2=1 AND id3=1 ORDER BY date DESC LIMIT 0,4; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range id_234_date,id_23_date id_23_date 2 NULL 8 Using where # See above query EXPLAIN SELECT id1 FROM t2 WHERE id2=1 AND id3=1 ORDER BY date DESC LIMIT 0,4; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 range id_23_date,id_234_date id_23_date 2 NULL 8 Using where drop table t1,t2; # # MDEV-8989: ORDER BY optimizer ignores equality propagation # set @tmp_8989=@@optimizer_switch; set optimizer_switch='orderby_uses_equalities=on'; create table t0(a int); insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); create table t1(a int); insert into t1 select A.a + B.a* 10 + C.a * 100 from t0 A, t0 B, t0 C; create table t2 ( pk int primary key, a int, b int, filler char(200), key(a) ); insert into t2 select a, 1000-a, 1000-a, repeat('abc-',50) from t1 where a<200 limit 200; create table t3 ( pk int primary key, a int, b int, filler char(200), key(a) ); insert into t3 select a, 1000-a, 1000-a, repeat('abc-',50) from t1; insert into t3 select a+1000, 1000+a, 1000+a, repeat('abc-',50) from t1; # The optimizer produces an order of 't2,t3' for this join # # Case #1 (from the bug report): # Q1 can take advantage of t2.a to resolve ORDER BY limit w/o sorting explain select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t2.a limit 5; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 index a a 5 NULL 5 Using where 1 SIMPLE t3 ref a a 5 test.t2.a 1 # # This is Q2 which used to have "Using temporary; using filesort" but # has the same query plan as Q1: # explain select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t3.a limit 5; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 index a a 5 NULL 5 Using where 1 SIMPLE t3 ref a a 5 test.t2.a 1 select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t2.a limit 5; pk a b pk a b 199 801 801 199 801 801 198 802 802 198 802 802 197 803 803 197 803 803 196 804 804 196 804 804 195 805 805 195 805 805 select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t3.a limit 5; pk a b pk a b 199 801 801 199 801 801 198 802 802 198 802 802 197 803 803 197 803 803 196 804 804 196 804 804 195 805 805 195 805 805 # # Case #2: here, only "Using temporary" is removed. "Using filesort" remains. # explain select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t2.a limit 25; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ALL a NULL NULL NULL 200 Using where; Using filesort 1 SIMPLE t3 ref a a 5 test.t2.a 1 explain select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t3.a limit 25; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ALL a NULL NULL NULL 200 Using where; Using filesort 1 SIMPLE t3 ref a a 5 test.t2.a 1 select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t2.a limit 25; pk a b pk a b 199 801 801 199 801 801 198 802 802 198 802 802 197 803 803 197 803 803 196 804 804 196 804 804 195 805 805 195 805 805 194 806 806 194 806 806 193 807 807 193 807 807 192 808 808 192 808 808 191 809 809 191 809 809 190 810 810 190 810 810 189 811 811 189 811 811 188 812 812 188 812 812 187 813 813 187 813 813 186 814 814 186 814 814 185 815 815 185 815 815 184 816 816 184 816 816 183 817 817 183 817 817 182 818 818 182 818 818 181 819 819 181 819 819 180 820 820 180 820 820 179 821 821 179 821 821 178 822 822 178 822 822 177 823 823 177 823 823 176 824 824 176 824 824 175 825 825 175 825 825 select t2.pk,t2.a,t2.b,t3.pk,t3.a,t3.b from t2, t3 where t2.a=t3.a order by t3.a limit 25; pk a b pk a b 199 801 801 199 801 801 198 802 802 198 802 802 197 803 803 197 803 803 196 804 804 196 804 804 195 805 805 195 805 805 194 806 806 194 806 806 193 807 807 193 807 807 192 808 808 192 808 808 191 809 809 191 809 809 190 810 810 190 810 810 189 811 811 189 811 811 188 812 812 188 812 812 187 813 813 187 813 813 186 814 814 186 814 814 185 815 815 185 815 815 184 816 816 184 816 816 183 817 817 183 817 817 182 818 818 182 818 818 181 819 819 181 819 819 180 820 820 180 820 820 179 821 821 179 821 821 178 822 822 178 822 822 177 823 823 177 823 823 176 824 824 176 824 824 175 825 825 175 825 825 # # Case #3: single table access (the code that decides whether we need # "Using temporary" is not invoked) # explain select * from t3 where b=a order by a limit 10; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t3 index NULL a 5 NULL 10 Using where # This must not use filesort. The query plan should be like the query above: explain select * from t3 where b=a order by b limit 10; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t3 index NULL a 5 NULL 10 Using where drop table t0,t1,t2,t3; set @@optimizer_switch=@tmp_8989; set optimizer_switch='orderby_uses_equalities=on'; # # MDEV-10880: Assertions `keypart_map' or # `prebuilt->search_tuple->n_fields > 0' fail on DISTINCT and # GROUP BY constant # CREATE TABLE t1 (pk INT PRIMARY KEY); INSERT INTO t1 VALUES (1),(2),(3); SELECT DISTINCT pk FROM t1 GROUP BY 'foo'; pk 1 SELECT DISTINCT pk FROM t1; pk 1 2 3 DROP TABLE t1; # # MDEV-21044: Wrong result when using a smaller size for sort buffer # create table t1(a varchar(765),b int); insert into t1 values ("a",1),("b",2),("c",3),("e",4); insert into t1 values ("d",5),("f",6),("g",7),("h",8); insert into t1 values ("k",11),("l",12),("i",9),("j",10); insert into t1 values ("m",13),("n",14),("o",15),("p",16); set @save_sort_buffer_size= @@sort_buffer_size; set sort_buffer_size=1024; select * from t1 order by b; a b a 1 b 2 c 3 e 4 d 5 f 6 g 7 h 8 i 9 j 10 k 11 l 12 m 13 n 14 o 15 p 16 set @@sort_buffer_size= @save_sort_buffer_size; drop table t1; # # MDEV-22715: SIGSEGV in radixsort_for_str_ptr and in native_compare/my_qsort2 (optimized builds) # SET @save_sort_buffer_size= @@sort_buffer_size; SET @save_max_sort_length= @@max_sort_length; SET max_sort_length=8; Warnings: Warning 1292 Truncated incorrect max_sort_length value: '8' SET sort_buffer_size=1024; CREATE TABLE t1(a INT, b DECIMAL(65), c BLOB); INSERT INTO t1 SELECT seq, seq, seq from seq_1_to_25; INSERT INTO t1 SELECT seq, seq, seq from seq_1_to_25; SELECT * FROM t1 ORDER BY a,b; a b c 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 6 6 6 6 6 6 7 7 7 7 7 7 8 8 8 8 8 8 9 9 9 9 9 9 10 10 10 10 10 10 11 11 11 11 11 11 12 12 12 12 12 12 13 13 13 13 13 13 14 14 14 14 14 14 15 15 15 15 15 15 16 16 16 16 16 16 17 17 17 17 17 17 18 18 18 18 18 18 19 19 19 19 19 19 20 20 20 20 20 20 21 21 21 21 21 21 22 22 22 22 22 22 23 23 23 23 23 23 24 24 24 24 24 24 25 25 25 25 25 25 SET @@sort_buffer_size= @save_sort_buffer_size; SET @@max_sort_length= @save_max_sort_length; DROP TABLE t1; # # MDEV-22390: Assertion `m_next_rec_ptr >= m_rawmem' failed in Filesort_buffer::spaceleft | # SIGSEGV in __memmove_avx_unaligned_erms from my_b_write (on optimized) # SET @save_max_sort_length= @@max_sort_length; SET @save_sort_buffer_size= @@sort_buffer_size; SET @save_max_length_for_sort_data= @@max_length_for_sort_data; SET max_sort_length=8; Warnings: Warning 1292 Truncated incorrect max_sort_length value: '8' SET sort_buffer_size=1024; SET max_length_for_sort_data=7000; CREATE TABLE t1(a VARCHAR(64), b VARCHAR(2048))DEFAULT CHARSET=utf8; INSERT INTO t1 SELECT seq,seq from seq_1_to_100; ANALYZE FORMAT=JSON SELECT * FROM t1 ORDER BY a LIMIT 5; ANALYZE { "query_optimization": { "r_total_time_ms": "REPLACED" }, "query_block": { "select_id": 1, "r_loops": 1, "r_total_time_ms": "REPLACED", "nested_loop": [ { "read_sorted_file": { "r_rows": 5, "filesort": { "sort_key": "t1.a", "r_loops": 1, "r_total_time_ms": "REPLACED", "r_limit": 5, "r_used_priority_queue": false, "r_output_rows": 100, "r_buffer_size": "REPLACED", "r_sort_mode": "sort_key,packed_addon_fields", "table": { "table_name": "t1", "access_type": "ALL", "r_loops": 1, "rows": 100, "r_rows": 100, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 100 } } } } ] } } SELECT * FROM t1 ORDER BY a LIMIT 5; a b 1 1 10 10 100 100 11 11 12 12 SET max_sort_length= @save_max_sort_length; SET sort_buffer_size= @save_sort_buffer_size; SET max_length_for_sort_data= @save_max_length_for_sort_data; DROP TABLE t1; # # MDEV-23596: Assertion `tab->ref.use_count' failed in join_read_key_unlock_row # CREATE TABLE t1 (a INT PRIMARY KEY, b INT, KEY(b)); INSERT INTO t1 VALUES (0, 1),(1, 2); CREATE TABLE t2 SELECT * FROM t1; EXPLAIN SELECT (SELECT 1 FROM t1 WHERE t1.a=t2.b ORDER BY t1.b LIMIT 1) AS c FROM t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 2 2 DEPENDENT SUBQUERY t1 eq_ref PRIMARY PRIMARY 4 test.t2.b 1 Using where SELECT (SELECT 1 FROM t1 WHERE t1.a=t2.b ORDER BY t1.b LIMIT 1) AS c FROM t2; c 1 NULL DROP TABLE t1,t2; # end of 10.1 tests # # MDEV-13994: Bad join results with orderby_uses_equalities=on # CREATE TABLE books ( id int(16) NOT NULL AUTO_INCREMENT, library_id int(16) NOT NULL DEFAULT 0, wings_id int(12) NOT NULL DEFAULT 0, scheduled_for_removal int(1) DEFAULT 0, PRIMARY KEY (id), KEY library_idx (library_id) ) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8; INSERT INTO books VALUES (32625,8663,707,0),(32624,8663,505,1); CREATE TABLE wings ( id int(11) NOT NULL AUTO_INCREMENT, department_id int(11) DEFAULT NULL, PRIMARY KEY (id) ) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8; INSERT INTO wings VALUES (505,11745),(707,11768); SET @save_optimizer_switch=@@optimizer_switch; SET optimizer_switch='orderby_uses_equalities=off'; SELECT wings.id as wing_id, wings.department_id FROM wings WHERE wings.id IN ( SELECT books.wings_id FROM books WHERE books.library_id = 8663 AND books.scheduled_for_removal=0 ) ORDER BY wings.id; wing_id department_id 707 11768 SET optimizer_switch='orderby_uses_equalities=on'; SELECT wings.id as wing_id, wings.department_id FROM wings WHERE wings.id IN ( SELECT books.wings_id FROM books WHERE books.library_id = 8663 AND books.scheduled_for_removal=0 ) ORDER BY wings.id; wing_id department_id 707 11768 explain extended SELECT wings.id as wing_id, wings.department_id FROM wings WHERE wings.id IN ( SELECT books.wings_id FROM books WHERE books.library_id = 8663 AND books.scheduled_for_removal=0 ) ORDER BY wings.id; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY ALL distinct_key NULL NULL NULL 2 100.00 Using filesort 1 PRIMARY wings eq_ref PRIMARY PRIMARY 4 test.books.wings_id 1 100.00 2 MATERIALIZED books ref library_idx library_idx 4 const 2 100.00 Using where Warnings: Note 1003 select `test`.`wings`.`id` AS `wing_id`,`test`.`wings`.`department_id` AS `department_id` from `test`.`wings` semi join (`test`.`books`) where `test`.`books`.`library_id` = 8663 and `test`.`books`.`scheduled_for_removal` = 0 and `test`.`wings`.`id` = `test`.`books`.`wings_id` order by `test`.`wings`.`id` set optimizer_switch= @save_optimizer_switch; DROP TABLE books, wings; # # MDEV-17796: query with DISTINCT, GROUP BY and ORDER BY # CREATE TABLE t1 (id int, gr int, v1 varchar(10)); INSERT INTO t1 VALUES (1,1,'A'), (2,2,'B'), (3,3,NULL), (4,4,'C'); SELECT DISTINCT NULLIF(GROUP_CONCAT(v1), null) FROM t1 WHERE gr in (4,2) GROUP BY id ORDER BY id+1 DESC; NULLIF(GROUP_CONCAT(v1), null) C B DROP TABLE t1; # # MDEV-24033: SIGSEGV in __memcmp_avx2_movbe from queue_insert | SIGSEGV in __memcmp_avx2_movbe from native_compare # SET @save_max_length_for_sort_data=@@max_length_for_sort_data; SET @save_max_sort_length= @@max_sort_length; SET @save_sql_select_limit= @@sql_select_limit; CREATE TABLE t1 (a DECIMAL(64,0), b INT); INSERT INTO t1 VALUES (1,1), (2,2), (3,3), (4,4); SET max_length_for_sort_data= 30; SET sql_select_limit = 3; SET max_sort_length=8; Warnings: Warning 1292 Truncated incorrect max_sort_length value: '8' SELECT * FROM t1 ORDER BY a+1; a b 1 1 2 2 3 3 SET max_length_for_sort_data=@save_max_length_for_sort_data; SET max_sort_length= @save_max_sort_length; SET sql_select_limit= @save_sql_select_limit; DROP TABLE t1; # # MDEV-25682: EXPLAIN for SELECT with ORDER BY after [ORDER BY] LIMIT # create table t1 (a int); insert into t1 values (3), (7), (1); explain (select a from t1 limit 2) order by a desc; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY ALL NULL NULL NULL NULL 2 Using filesort 2 DERIVED t1 ALL NULL NULL NULL NULL 3 (select a from t1 limit 2) order by a desc; a 7 3 create table t2 (a int, b int); insert into t2 values (3,70), (7,10), (1,40), (4,30); explain (select b,a from t2 order by a limit 3) order by b desc; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY ALL NULL NULL NULL NULL 3 Using filesort 2 DERIVED t2 ALL NULL NULL NULL NULL 4 Using filesort (select b,a from t2 order by a limit 3) order by b desc; b a 70 3 40 1 30 4 drop table t1,t2; # # MDEV-22256 Assertion `length == pack_length()' failed in Field_timestamp_with_dec::sort_string # SET sql_mode=''; SET @@SESSION.max_sort_length=4; Warnings: Warning 1292 Truncated incorrect max_sort_length value: '4' CREATE TABLE t1 (c TIMESTAMP(1)); INSERT INTO t1 VALUES(0); DELETE FROM t1 ORDER BY c; DROP TABLE t1; SET @@SESSION.max_sort_length=DEFAULT; SET sql_mode=DEFAULT; SET sql_mode=''; SET @@SESSION.max_sort_length=1; Warnings: Warning 1292 Truncated incorrect max_sort_length value: '1' CREATE TEMPORARY TABLE t1 (c DATETIME); INSERT INTO t1 VALUES(0); DELETE FROM t1 ORDER BY c; DROP TABLE t1; SET @@SESSION.max_sort_length=DEFAULT; SET sql_mode=DEFAULT; # # MDEV-25994 Crash with union of my_decimal type in ORDER BY clause # CREATE TABLE t1 (v1 INTEGER) ; INSERT INTO t1 (v1) VALUES (8); UPDATE t1 SET v1 = 1 ORDER BY (SELECT 1.1 UNION SELECT -1); ERROR 21000: Subquery returns more than 1 row # This one must be successful UPDATE t1 SET v1 = 2 ORDER BY (SELECT 1 UNION SELECT 1); UPDATE t1 SET v1 = 3 ORDER BY (SELECT 'a' UNION SELECT 'b'); ERROR 21000: Subquery returns more than 1 row # Insert some more data INSERT INTO t1 (v1) VALUES (8),(9),(100),(-234),(46584),(0); UPDATE t1 SET v1 = v1+1 ORDER BY (SELECT 100.122 UNION SELECT -189.2); ERROR 21000: Subquery returns more than 1 row # This one must be successful UPDATE t1 SET v1 = v1-200 ORDER BY (SELECT 1 UNION SELECT 1); UPDATE t1 SET v1 = v1 ORDER BY (SELECT 'abc' UNION SELECT 'bbb'); ERROR 21000: Subquery returns more than 1 row DROP TABLE t1; # End of 10.2 tests # # MDEV-16214: Incorrect plan taken by the optimizer , uses INDEX instead of ref access with ORDER BY # create table t1(a int); insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); create table t2( id int primary key, key1 int,key2 int, col1 int, key(key1), key(key2) ); insert into t2 select A.a + B.a*10 + C.a*100, A.a + 10*B.a, A.a + 10*B.a, 123456 from t1 A, t1 B, t1 C; # here type should show ref not index explain select (SELECT concat(id, '-', key1, '-', col1) FROM t2 WHERE t2.key1 = t1.a and t2.key1 IS NOT NULL ORDER BY t2.key2 ASC LIMIT 1) from t1; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t1 ALL NULL NULL NULL NULL 10 2 DEPENDENT SUBQUERY t2 ref key1 key1 5 test.t1.a 10 Using index condition; Using where; Using filesort select (SELECT concat(id, '-', key1, '-', col1) FROM t2 WHERE t2.key1 = t1.a and t2.key1 IS NOT NULL ORDER BY t2.key2 ASC LIMIT 1) from t1; (SELECT concat(id, '-', key1, '-', col1) FROM t2 WHERE t2.key1 = t1.a and t2.key1 IS NOT NULL ORDER BY t2.key2 ASC LIMIT 1) 900-0-123456 901-1-123456 902-2-123456 903-3-123456 904-4-123456 905-5-123456 906-6-123456 907-7-123456 908-8-123456 909-9-123456 drop table t1,t2; # End of 10.3 tests # # MDEV-17761: Odd optimizer choice with ORDER BY LIMIT and condition selectivity # create table t1(a int); insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); create table t2(a int); insert into t2 select A.a + B.a* 10 + C.a * 100 from t1 A, t1 B, t1 C; create table t3(a int); insert into t3 select A.a + 1000 *B.a from t2 A, t1 B; create table t4 ( a int, b int, c int, filler1 char(255), filler2 char(255), key(a) ); insert into t4 select a,a,a, a,a from t3; set @tmp_h=@@histogram_size, @tmp_ht=@@histogram_type, @tmp_u=@@use_stat_tables, @tmp_o=@@optimizer_use_condition_selectivity; set histogram_size=100, histogram_type='single_prec_hb'; set use_stat_tables=preferably; set optimizer_use_condition_selectivity=4; analyze table t4 persistent for columns(b) indexes (); Table Op Msg_type Msg_text test.t4 analyze status Engine-independent statistics collected test.t4 analyze status Table is already up to date # rows must be around 1200, not 600: explain extended select * from t4 where b < 5000 order by a limit 600; id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE t4 index NULL a 5 NULL 1188 100.00 Using where Warnings: Note 1003 select `test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t4`.`c` AS `c`,`test`.`t4`.`filler1` AS `filler1`,`test`.`t4`.`filler2` AS `filler2` from `test`.`t4` where `test`.`t4`.`b` < 5000 order by `test`.`t4`.`a` limit 600 set histogram_size=@tmp_h, histogram_type=@tmp_ht, use_stat_tables=@tmp_u, optimizer_use_condition_selectivity=@tmp_o; drop table t1,t2,t3,t4; # # MDEV-32324: Server crashes inside filesort at my_decimal::to_binary # SELECT 1.000000 two UNION SELECT 1 ORDER BY ( SELECT two LIMIT 1 OFFSET 1 ) ; two 1.000000 # MDEV-32475: test_if_skip_sort_order() should catch the join types # JT_EQ_REF, JT_CONST and JT_SYSTEM and skip sort order for these # CREATE TABLE t1 (a INT PRIMARY KEY, b INT, KEY(b)); CREATE TABLE t2 (a INT, b INT); INSERT INTO t1 SELECT seq, seq+1 FROM seq_1_to_100; INSERT INTO t2 VALUES (0, 1),(1, 2); ANALYZE TABLE t1, t2 PERSISTENT FOR ALL; Table Op Msg_type Msg_text test.t1 analyze status Engine-independent statistics collected test.t1 analyze status Table is already up to date test.t2 analyze status Engine-independent statistics collected test.t2 analyze status OK # Table t1 must use eq_ref, not index below: EXPLAIN SELECT (SELECT 1 FROM t1 WHERE t1.a=t2.b ORDER BY t1.b LIMIT 1) AS c FROM t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 2 2 DEPENDENT SUBQUERY t1 eq_ref PRIMARY PRIMARY 4 test.t2.b 1 Using where DROP TABLE t1,t2; # End of 10.4 tests # # MDEV-21655: Server crashes in my_qsort2 / Filesort_buffer::sort_buffer # set @save_sql_mode= @@sql_mode; set sql_mode= 'PAD_CHAR_TO_FULL_LENGTH'; CREATE TABLE t1 ( a CHAR(255), b CHAR(255), c TEXT); INSERT INTO t1 VALUES ('1','a', 'a'), ('2','b', 'b'), ('3','c', 'c'), ('4','d','d'), ('5','e', 'e'), ('6','f', 'f'), ('7','g','g'), ('8','h','h'), ('9','i', 'i'), ('10','j','j'), ('11','k','k'), ('12','l','l'), ('13','m','m'), ('14','n','n'), ('15','o','o'); set sort_buffer_size=524*15; select c from t1 order by a,b; c a j k l m n o b c d e f g h i set sort_buffer_size= default; set sql_mode= @save_sql_mode; drop table t1; # # MDEV-21580: Allow packed sort keys in sort buffer # # # This example should not pack sort keys # all fields are fixed-size fields in the ORDER BY clause # create table t1 (a bigint, b bigint, c bigint); insert into t1 select seq, seq, seq from seq_1_to_100; # in r_sort_mode it should show sort_key and not packed_sort_key ANALYZE FORMAT=JSON select * from t1 order by a,b,c; ANALYZE { "query_optimization": { "r_total_time_ms": "REPLACED" }, "query_block": { "select_id": 1, "r_loops": 1, "r_total_time_ms": "REPLACED", "nested_loop": [ { "read_sorted_file": { "r_rows": 100, "filesort": { "sort_key": "t1.a, t1.b, t1.c", "r_loops": 1, "r_total_time_ms": "REPLACED", "r_used_priority_queue": false, "r_output_rows": 100, "r_buffer_size": "REPLACED", "r_sort_mode": "sort_key,packed_addon_fields", "table": { "table_name": "t1", "access_type": "ALL", "r_loops": 1, "rows": 100, "r_rows": 100, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 100 } } } } ] } } select * from t1 order by a,b,c; a b c 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 8 8 8 9 9 9 10 10 10 11 11 11 12 12 12 13 13 13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 20 20 20 21 21 21 22 22 22 23 23 23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 30 30 30 31 31 31 32 32 32 33 33 33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 40 40 40 41 41 41 42 42 42 43 43 43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 50 50 50 51 51 51 52 52 52 53 53 53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 59 59 59 60 60 60 61 61 61 62 62 62 63 63 63 64 64 64 65 65 65 66 66 66 67 67 67 68 68 68 69 69 69 70 70 70 71 71 71 72 72 72 73 73 73 74 74 74 75 75 75 76 76 76 77 77 77 78 78 78 79 79 79 80 80 80 81 81 81 82 82 82 83 83 83 84 84 84 85 85 85 86 86 86 87 87 87 88 88 88 89 89 89 90 90 90 91 91 91 92 92 92 93 93 93 94 94 94 95 95 95 96 96 96 97 97 97 98 98 98 99 99 99 100 100 100 drop table t1; # # Test with Binary columns (using suffix length to determine ordering) # Should show packed_sortkey in the r_sort_mode # create table t1 (a int, b blob); set @save_max_sort_length= @@max_sort_length; insert into t1 select 1, CONCAT(repeat('a', @save_max_sort_length), 'A'); insert into t1 select 2, CONCAT(repeat('a', @save_max_sort_length), 'AB'); insert into t1 select 3, CONCAT(repeat('a', @save_max_sort_length), 'ABE'); insert into t1 select 4, CONCAT(repeat('a', @save_max_sort_length), 'APBX'); insert into t1 select 5, CONCAT(repeat('a', @save_max_sort_length), 'ABAAX'); show variables like '%sort_buffer_size'; Variable_name Value aria_sort_buffer_size 268434432 myisam_sort_buffer_size 134216704 sort_buffer_size 262144 select a, substr(b, @save_max_sort_length+1) from t1 order by b desc; a substr(b, @save_max_sort_length+1) 5 ABAAX 4 APBX 3 ABE 2 AB 1 A analyze format=json select a, substr(b, @save_max_sort_length+1) from t1 order by b desc; ANALYZE { "query_optimization": { "r_total_time_ms": "REPLACED" }, "query_block": { "select_id": 1, "r_loops": 1, "r_total_time_ms": "REPLACED", "nested_loop": [ { "read_sorted_file": { "r_rows": 5, "filesort": { "sort_key": "t1.b desc", "r_loops": 1, "r_total_time_ms": "REPLACED", "r_used_priority_queue": false, "r_output_rows": 5, "r_buffer_size": "REPLACED", "r_sort_mode": "packed_sort_key,rowid", "table": { "table_name": "t1", "access_type": "ALL", "r_loops": 1, "rows": 5, "r_rows": 5, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 100 } } } } ] } } drop table t1; # # Packing sort keys with complex collations # create table t1(a varchar(255) charset utf8, b int, c decimal); insert into t1 values ('abc', 1, 1) , ('bcd', 2, 2), ('cde',3, 3); insert into t1 values ('def', 4, 4) , ('efg', 5, 5), ('fgh', 6, 6); # # Should show packed_sortkey in the r_sort_mode # ANALYZE FORMAT=JSON select a, b, c from t1 order by a, b; ANALYZE { "query_optimization": { "r_total_time_ms": "REPLACED" }, "query_block": { "select_id": 1, "r_loops": 1, "r_total_time_ms": "REPLACED", "nested_loop": [ { "read_sorted_file": { "r_rows": 6, "filesort": { "sort_key": "t1.a, t1.b", "r_loops": 1, "r_total_time_ms": "REPLACED", "r_used_priority_queue": false, "r_output_rows": 6, "r_buffer_size": "REPLACED", "r_sort_mode": "packed_sort_key,rowid", "table": { "table_name": "t1", "access_type": "ALL", "r_loops": 1, "rows": 6, "r_rows": 6, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 100 } } } } ] } } select a, b, c from t1 order by a, b; a b c abc 1 1 bcd 2 2 cde 3 3 def 4 4 efg 5 5 fgh 6 6 set @save_max_sort_length= @@max_sort_length; set max_sort_length=5; Warnings: Warning 1292 Truncated incorrect max_sort_length value: '5' # # should show sortkey in r_sort_mode as the collation is complex and # truncation is not possible # ANALYZE FORMAT=JSON select a, b, c from t1 order by a, b; ANALYZE { "query_optimization": { "r_total_time_ms": "REPLACED" }, "query_block": { "select_id": 1, "r_loops": 1, "r_total_time_ms": "REPLACED", "nested_loop": [ { "read_sorted_file": { "r_rows": 6, "filesort": { "sort_key": "t1.a, t1.b", "r_loops": 1, "r_total_time_ms": "REPLACED", "r_used_priority_queue": false, "r_output_rows": 6, "r_buffer_size": "REPLACED", "r_sort_mode": "sort_key,packed_addon_fields", "table": { "table_name": "t1", "access_type": "ALL", "r_loops": 1, "rows": 6, "r_rows": 6, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 100 } } } } ] } } select a, b, c from t1 order by a, b; a b c abc 1 1 bcd 2 2 cde 3 3 def 4 4 efg 5 5 fgh 6 6 set max_sort_length= @save_max_sort_length; drop table t1; # # MDEV-21922: Allow packing addon fields even if they don't honour max_length_for_sort_data # create table t1 (a varchar(200) character set utf8, b int); insert into t1 select seq, seq from seq_1_to_10; select * from t1 order by a; a b 1 1 10 10 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 # # r_sort_mode should show both packed_sort_key and packed_addon_fields # analyze format=json select * from t1 order by a; ANALYZE { "query_optimization": { "r_total_time_ms": "REPLACED" }, "query_block": { "select_id": 1, "r_loops": 1, "r_total_time_ms": "REPLACED", "nested_loop": [ { "read_sorted_file": { "r_rows": 10, "filesort": { "sort_key": "t1.a", "r_loops": 1, "r_total_time_ms": "REPLACED", "r_used_priority_queue": false, "r_output_rows": 10, "r_buffer_size": "REPLACED", "r_sort_mode": "packed_sort_key,packed_addon_fields", "table": { "table_name": "t1", "access_type": "ALL", "r_loops": 1, "rows": 10, "r_rows": 10, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 100 } } } } ] } } drop table t1; # # MDEV-21946: Server crash in store_length upon GROUP BY WITH ROLLUP with geometry field # create table t1 ( a longblob); insert into t1 select repeat('a', 256); insert into t1 select repeat('b', 256); insert into t1 select repeat('c', 256); insert into t1 select repeat('d', 256); SELECT IF( 0, NULL, a ) AS f FROM t1 GROUP BY f WITH ROLLUP; f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd NULL DROP TABLE t1; # # MDEV-22303: Incorrect ordering with REGEXP_REPLACE and OFFSET/LIMIT # CREATE TABLE t1 (name VARCHAR(20) CHARACTER SET utf8 NOT NULL); INSERT INTO t1 (name) VALUES ('Charles Dickens'), ('Roald Dahl'); SELECT name, REGEXP_REPLACE(name, '^(.*) (.*)$', '\\2, \\1') AS surname_first FROM t1 ORDER BY surname_first ASC; name surname_first Roald Dahl Dahl, Roald Charles Dickens Dickens, Charles SELECT name, REGEXP_REPLACE(name, '^(.*) (.*)$', '\\2, \\1') AS surname_first FROM t1 ORDER BY surname_first ASC LIMIT 1; name surname_first Roald Dahl Dahl, Roald SELECT name, REGEXP_REPLACE(name, '^(.*) (.*)$', '\\2, \\1') AS surname_first FROM t1 ORDER BY surname_first ASC LIMIT 1 OFFSET 1; name surname_first Charles Dickens Dickens, Charles DROP TABLE t1; # # MDEV-22836: Server crashes in err_conv / ErrBuff::set_str # CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (0),(1); SELECT * FROM t1 ORDER BY CONVERT(AES_ENCRYPT(1,a), CHAR(4)); a 1 0 DROP TABLE t1; # # MDEV-22819:Wrong result or Assertion `ix > 0' failed in read_to_buffer upon select # with GROUP BY and GROUP_CONCAT # CREATE TABLE t1 (a VARCHAR(1000), b CHAR(1)); INSERT INTO t1 VALUES (REPEAT('a',1000),'a'),(REPEAT('t',932),'t'),('x',NULL),('x',NULL), (REPEAT('z',298),'z'),(REPEAT('p',1000),'p'),(REPEAT('k',468),'k'), (REPEAT('c',1000),'c'),(REPEAT('o',648),'o'),('x',NULL),('x',NULL), (REPEAT('c',258),'c'),(REPEAT('t',414),'t'),(REPEAT('f',966),'f'), (REPEAT('y',746),'y'),(REPEAT('f',1000),'f'); INSERT INTO t1 SELECT * FROM t1; INSERT INTO t1 SELECT * FROM t1; INSERT INTO t1 SELECT * FROM t1; INSERT INTO t1 SELECT * FROM t1; SET @save_sort_buffer_size= @@sort_buffer_size; SET sort_buffer_size= 16384; SELECT LEFT(a,1), GROUP_CONCAT(b) FROM t1 GROUP BY a; LEFT(a,1) GROUP_CONCAT(b) a a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a c c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c c c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c f f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f f f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f k k,k,k,k,k,k,k,k,k,k,k,k,k,k,k,k o o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o p p,p,p,p,p,p,p,p,p,p,p,p,p,p,p,p t t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t t t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t x NULL y y,y,y,y,y,y,y,y,y,y,y,y,y,y,y,y z z,z,z,z,z,z,z,z,z,z,z,z,z,z,z,z SELECT SUBSTR(a,1,1), LENGTH(a), GROUP_CONCAT(b), COUNT(*) FROM t1 GROUP BY a; SUBSTR(a,1,1) LENGTH(a) GROUP_CONCAT(b) COUNT(*) a 1000 a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a 16 c 258 c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c 16 c 1000 c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c 16 f 966 f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f 16 f 1000 f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f 16 k 468 k,k,k,k,k,k,k,k,k,k,k,k,k,k,k,k 16 o 648 o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o 16 p 1000 p,p,p,p,p,p,p,p,p,p,p,p,p,p,p,p 16 t 414 t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t 16 t 932 t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t 16 x 1 NULL 64 y 746 y,y,y,y,y,y,y,y,y,y,y,y,y,y,y,y 16 z 298 z,z,z,z,z,z,z,z,z,z,z,z,z,z,z,z 16 SET @@sort_buffer_size= @save_sort_buffer_size; DROP TABLE t1; CREATE TABLE t1(a VARCHAR(1027), b INT); INSERT INTO t1 SELECT seq, seq from seq_1_to_34; SET @save_tmp_memory_table_size= @@tmp_memory_table_size; SET tmp_memory_table_size= 1056*2; SELECT COUNT(DISTINCT a) FROM t1; COUNT(DISTINCT a) 34 SET @@tmp_memory_table_size= @save_tmp_memory_table_size; DROP TABLE t1; # # MDEV-23216: LONGTEXT column with collation doesn't sort # CREATE TABLE t1 (a LONGTEXT COLLATE utf8mb4_swedish_ci); INSERT INTO t1 VALUES ('A'),('Z'),('B'),('Y'); SELECT * FROM t1 ORDER BY a; a A B Y Z SELECT * FROM t1 ORDER BY a DESC; a Z Y B A DROP TABLE t1; # # MDEV-23414 Assertion `res->charset() == item->collation.collation' failed in Type_handler_string_result::make_packed_sort_key_part # CREATE TABLE t1 (a CHAR(3), b BINARY(255)); INSERT t1 VALUES ('foo','bar'),('baz','qux'); SELECT COALESCE(a, b) AS f FROM t1 ORDER BY f; f baz foo DROP TABLE t1; # # MDEV-24015: SQL Error (1038): Out of sort memory when enough memory for the # sort buffer is provided # CREATE TABLE t1 (a VARCHAR(100), b INT); CREATE TABLE t2 (a VARCHAR(100), b INT); INSERT INTO t1 SELECT 'abc', seq FROM seq_1_to_50; INSERT INTO t2 SELECT seq, seq FROM seq_1_to_50; set @save_sort_buffer_size= @@sort_buffer_size; set sort_buffer_size=2000; ANALYZE FORMAT=JSON SELECT (SELECT sum(t2.b) FROM t2 WHERE t1.b=t2.b GROUP BY t2.a) FROM t1; ANALYZE { "query_optimization": { "r_total_time_ms": "REPLACED" }, "query_block": { "select_id": 1, "r_loops": 1, "r_total_time_ms": "REPLACED", "nested_loop": [ { "table": { "table_name": "t1", "access_type": "ALL", "r_loops": 1, "rows": 50, "r_rows": 50, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 100 } } ], "subqueries": [ { "expression_cache": { "r_loops": 50, "r_hit_ratio": 0, "query_block": { "select_id": 2, "r_loops": 50, "r_total_time_ms": "REPLACED", "filesort": { "sort_key": "t2.a", "r_loops": 50, "r_total_time_ms": "REPLACED", "r_used_priority_queue": false, "r_output_rows": 1, "r_buffer_size": "REPLACED" across executions)", "r_sort_mode": "sort_key,rowid", "temporary_table": { "nested_loop": [ { "table": { "table_name": "t2", "access_type": "ALL", "r_loops": 50, "rows": 50, "r_rows": 50, "r_table_time_ms": "REPLACED", "r_other_time_ms": "REPLACED", "r_engine_stats": REPLACED, "filtered": 100, "r_filtered": 2, "attached_condition": "t1.b = t2.b" } } ] } } } } } ] } } SELECT (SELECT sum(t2.b) FROM t2 WHERE t1.b=t2.b GROUP BY t2.a) FROM t1; (SELECT sum(t2.b) FROM t2 WHERE t1.b=t2.b GROUP BY t2.a) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 set sort_buffer_size= @save_sort_buffer_size; DROP TABLE t1,t2; # End of 10.5 tests # # MDEV-13694: Wrong result upon GROUP BY with orderby_uses_equalities=on # CREATE TABLE t1 (a INT, b int, primary key(a)); CREATE TABLE t2 (a INT, b INT); INSERT INTO t1 (a,b) VALUES (58,1),(96,2),(273,3),(23,4),(231,5),(525,6), (2354,7),(321421,3),(535,2),(4535,3); INSERT INTO t2 (a,b) VALUES (58,3),(96,3),(273,3); # Join order should have the SJM scan table as the first table for both # the queries with GROUP BY and ORDER BY clause. EXPLAIN SELECT t1.a FROM t1 WHERE t1.a IN (SELECT a FROM t2 WHERE b=3) ORDER BY t1.a DESC; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY ALL distinct_key NULL NULL NULL 3 Using filesort 1 PRIMARY t1 eq_ref PRIMARY PRIMARY 4 test.t2.a 1 Using index 2 MATERIALIZED t2 ALL NULL NULL NULL NULL 3 Using where EXPLAIN FORMAT=JSON SELECT t1.a FROM t1 WHERE t1.a IN (SELECT a FROM t2 WHERE b=3) ORDER BY t1.a DESC; EXPLAIN { "query_block": { "select_id": 1, "nested_loop": [ { "read_sorted_file": { "filesort": { "sort_key": "t1.a desc", "table": { "table_name": "", "access_type": "ALL", "possible_keys": ["distinct_key"], "rows": 3, "filtered": 100, "materialized": { "unique": 1, "query_block": { "select_id": 2, "nested_loop": [ { "table": { "table_name": "t2", "access_type": "ALL", "rows": 3, "filtered": 100, "attached_condition": "t2.b = 3 and t2.a is not null" } } ] } } } } } }, { "table": { "table_name": "t1", "access_type": "eq_ref", "possible_keys": ["PRIMARY"], "key": "PRIMARY", "key_length": "4", "used_key_parts": ["a"], "ref": ["test.t2.a"], "rows": 1, "filtered": 100, "using_index": true } } ] } } SELECT t1.a FROM t1 WHERE t1.a IN (SELECT a FROM t2 WHERE b=3) ORDER BY t1.a DESC; a 273 96 58 EXPLAIN SELECT t1.a, group_concat(t1.b) FROM t1 WHERE t1.a IN (SELECT a FROM t2 WHERE b=3) GROUP BY t1.a DESC; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY ALL distinct_key NULL NULL NULL 3 Using filesort 1 PRIMARY t1 eq_ref PRIMARY PRIMARY 4 test.t2.a 1 2 MATERIALIZED t2 ALL NULL NULL NULL NULL 3 Using where EXPLAIN FORMAT=JSON SELECT t1.a, group_concat(t1.b) FROM t1 WHERE t1.a IN (SELECT a FROM t2 WHERE b=3) GROUP BY t1.a DESC; EXPLAIN { "query_block": { "select_id": 1, "nested_loop": [ { "read_sorted_file": { "filesort": { "sort_key": "t1.a desc", "table": { "table_name": "", "access_type": "ALL", "possible_keys": ["distinct_key"], "rows": 3, "filtered": 100, "materialized": { "unique": 1, "query_block": { "select_id": 2, "nested_loop": [ { "table": { "table_name": "t2", "access_type": "ALL", "rows": 3, "filtered": 100, "attached_condition": "t2.b = 3 and t2.a is not null" } } ] } } } } } }, { "table": { "table_name": "t1", "access_type": "eq_ref", "possible_keys": ["PRIMARY"], "key": "PRIMARY", "key_length": "4", "used_key_parts": ["a"], "ref": ["test.t2.a"], "rows": 1, "filtered": 100 } } ] } } SELECT t1.a, group_concat(t1.b) FROM t1 WHERE t1.a IN (SELECT a FROM t2 WHERE b=3) GROUP BY t1.a DESC; a group_concat(t1.b) 273 3 96 2 58 1 DROP TABLE t1, t2; # End of 10.6 tests # # MDEV-13756 Implement descending index: KEY (a DESC, b ASC) # create table t1 (a int, b int, c int, key r (a desc, b asc)); insert t1 select seq % 10, seq div 10, seq from seq_1_to_55; insert t1 values (NULL, NULL, NULL), (9, NULL, NULL); explain select * from t1 force index(r) order by a,b limit 20; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 57 Using filesort explain select * from t1 force index(r) order by a desc,b limit 20; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL r 10 NULL 20 select * from t1 force index(r) order by a desc,b limit 20; a b c 9 NULL NULL 9 0 9 9 1 19 9 2 29 9 3 39 9 4 49 8 0 8 8 1 18 8 2 28 8 3 38 8 4 48 7 0 7 7 1 17 7 2 27 7 3 37 7 4 47 6 0 6 6 1 16 6 2 26 6 3 36 drop table t1;