set optimizer_switch='batched_key_access=on,mrr_cost_based=off';
drop table if exists t0,t1,t2,t3,t4,t5;
CREATE TABLE t1 (
grp int(11) default NULL,
a bigint(20) unsigned default NULL,
c char(10) NOT NULL default ''
) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,1,'a'),(2,2,'b'),(2,3,'c'),(3,4,'E'),(3,5,'C'),(3,6,'D'),(NULL,NULL,'');
create table t2 (id int, a bigint unsigned not null, c char(10), d int, primary key (a));
insert into t2 values (1,1,"a",1),(3,4,"A",4),(3,5,"B",5),(3,6,"C",6),(4,7,"D",7);
select t1.*,t2.* from t1 JOIN t2 where t1.a=t2.a;
grp a c id a c d
1 1 a 1 1 a 1
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
select t1.*,t2.* from t1 left join t2 on (t1.a=t2.a) order by t1.grp,t1.a,t2.c;
grp a c id a c d
NULL NULL NULL NULL NULL NULL
1 1 a 1 1 a 1
2 2 b NULL NULL NULL NULL
2 3 c NULL NULL NULL NULL
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
select t1.*,t2.* from { oj t2 left outer join t1 on (t1.a=t2.a) };
grp a c id a c d
1 1 a 1 1 a 1
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
NULL NULL NULL 4 7 D 7
select t1.*,t2.* from t1 as t0,{ oj t2 left outer join t1 on (t1.a=t2.a) } WHERE t0.a=2;
grp a c id a c d
1 1 a 1 1 a 1
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
NULL NULL NULL 4 7 D 7
select t1.*,t2.* from t1 left join t2 using (a);
grp a c id a c d
1 1 a 1 1 a 1
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
2 2 b NULL NULL NULL NULL
2 3 c NULL NULL NULL NULL
NULL NULL NULL NULL NULL NULL
select t1.*,t2.* from t1 left join t2 using (a) where t1.a=t2.a;
grp a c id a c d
1 1 a 1 1 a 1
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
select t1.*,t2.* from t1 left join t2 using (a,c);
grp a c id a c d
1 1 a 1 1 a 1
2 2 b NULL NULL NULL NULL
2 3 c NULL NULL NULL NULL
3 4 E NULL NULL NULL NULL
3 5 C NULL NULL NULL NULL
3 6 D NULL NULL NULL NULL
NULL NULL NULL NULL NULL NULL
select t1.*,t2.* from t1 left join t2 using (c);
grp a c id a c d
1 1 a 1 1 a 1
1 1 a 3 4 A 4
2 2 b 3 5 B 5
2 3 c 3 6 C 6
3 4 E NULL NULL NULL NULL
3 5 C 3 6 C 6
3 6 D 4 7 D 7
NULL NULL NULL NULL NULL NULL
select t1.*,t2.* from t1 natural left outer join t2;
grp a c id a c d
1 1 a 1 1 a 1
2 2 b NULL NULL NULL NULL
2 3 c NULL NULL NULL NULL
3 4 E NULL NULL NULL NULL
3 5 C NULL NULL NULL NULL
3 6 D NULL NULL NULL NULL
NULL NULL NULL NULL NULL NULL
select t1.*,t2.* from t1 left join t2 on (t1.a=t2.a) where t2.id=3;
grp a c id a c d
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
select t1.*,t2.* from t1 left join t2 on (t1.a=t2.a) where t2.id is null;
grp a c id a c d
2 2 b NULL NULL NULL NULL
2 3 c NULL NULL NULL NULL
NULL NULL NULL NULL NULL NULL
explain select t1.*,t2.* from t1,t2 where t1.a=t2.a and isnull(t2.a)=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
explain select t1.*,t2.* from t1 left join t2 on t1.a=t2.a where isnull(t2.a)=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 7 NULL
1 SIMPLE t2 ALL PRIMARY NULL NULL NULL 5 Using where; Using join buffer (Block Nested Loop)
select t1.*,t2.*,t3.a from t1 left join t2 on (t1.a=t2.a) left join t1 as t3 on (t2.a=t3.a);
grp a c id a c d a
1 1 a 1 1 a 1 1
2 2 b NULL NULL NULL NULL NULL
2 3 c NULL NULL NULL NULL NULL
3 4 E 3 4 A 4 4
3 5 C 3 5 B 5 5
3 6 D 3 6 C 6 6
NULL NULL NULL NULL NULL NULL NULL
explain select t1.*,t2.*,t3.a from t1 left join t2 on (t3.a=t2.a) left join t1 as t3 on (t1.a=t3.a);
ERROR 42S22: Unknown column 't3.a' in 'on clause'
select t1.*,t2.*,t3.a from t1 left join t2 on (t3.a=t2.a) left join t1 as t3 on (t1.a=t3.a);
ERROR 42S22: Unknown column 't3.a' in 'on clause'
select t1.*,t2.*,t3.a from t1 left join t2 on (t3.a=t2.a) left join t1 as t3 on (t2.a=t3.a);
ERROR 42S22: Unknown column 't3.a' in 'on clause'
select t1.*,t2.* from t1 inner join t2 using (a);
grp a c id a c d
1 1 a 1 1 a 1
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
select t1.*,t2.* from t1 inner join t2 on (t1.a=t2.a);
grp a c id a c d
1 1 a 1 1 a 1
3 4 E 3 4 A 4
3 5 C 3 5 B 5
3 6 D 3 6 C 6
select t1.*,t2.* from t1 natural join t2;
grp a c id a c d
1 1 a 1 1 a 1
drop table t1,t2;
CREATE TABLE t1 (
usr_id INT unsigned NOT NULL,
uniq_id INT unsigned NOT NULL AUTO_INCREMENT,
start_num INT unsigned NOT NULL DEFAULT 1,
increment INT unsigned NOT NULL DEFAULT 1,
PRIMARY KEY (uniq_id),
INDEX usr_uniq_idx (usr_id, uniq_id),
INDEX uniq_usr_idx (uniq_id, usr_id)
);
CREATE TABLE t2 (
id INT unsigned NOT NULL DEFAULT 0,
usr2_id INT unsigned NOT NULL DEFAULT 0,
max INT unsigned NOT NULL DEFAULT 0,
c_amount INT unsigned NOT NULL DEFAULT 0,
d_max INT unsigned NOT NULL DEFAULT 0,
d_num INT unsigned NOT NULL DEFAULT 0,
orig_time INT unsigned NOT NULL DEFAULT 0,
c_time INT unsigned NOT NULL DEFAULT 0,
active ENUM ("no","yes") NOT NULL,
PRIMARY KEY (id,usr2_id),
INDEX id_idx (id),
INDEX usr2_idx (usr2_id)
);
INSERT INTO t1 VALUES (3,NULL,0,50),(3,NULL,0,200),(3,NULL,0,25),(3,NULL,0,84676),(3,NULL,0,235),(3,NULL,0,10),(3,NULL,0,3098),(3,NULL,0,2947),(3,NULL,0,8987),(3,NULL,0,8347654),(3,NULL,0,20398),(3,NULL,0,8976),(3,NULL,0,500),(3,NULL,0,198);
SELECT t1.usr_id,t1.uniq_id,t1.increment,
t2.usr2_id,t2.c_amount,t2.max
FROM t1
LEFT JOIN t2 ON t2.id = t1.uniq_id
WHERE t1.uniq_id = 4
ORDER BY t2.c_amount;
usr_id uniq_id increment usr2_id c_amount max
3 4 84676 NULL NULL NULL
SELECT t1.usr_id,t1.uniq_id,t1.increment,
t2.usr2_id,t2.c_amount,t2.max
FROM t2
RIGHT JOIN t1 ON t2.id = t1.uniq_id
WHERE t1.uniq_id = 4
ORDER BY t2.c_amount;
usr_id uniq_id increment usr2_id c_amount max
3 4 84676 NULL NULL NULL
INSERT INTO t2 VALUES (2,3,3000,6000,0,0,746584,837484,'yes');
INSERT INTO t2 VALUES (2,3,3000,6000,0,0,746584,837484,'yes');
ERROR 23000: Duplicate entry '2-3' for key 'PRIMARY'
INSERT INTO t2 VALUES (7,3,1000,2000,0,0,746294,937484,'yes');
SELECT t1.usr_id,t1.uniq_id,t1.increment,t2.usr2_id,t2.c_amount,t2.max FROM t1 LEFT JOIN t2 ON t2.id = t1.uniq_id WHERE t1.uniq_id = 4 ORDER BY t2.c_amount;
usr_id uniq_id increment usr2_id c_amount max
3 4 84676 NULL NULL NULL
SELECT t1.usr_id,t1.uniq_id,t1.increment,t2.usr2_id,t2.c_amount,t2.max FROM t1 LEFT JOIN t2 ON t2.id = t1.uniq_id WHERE t1.uniq_id = 4 GROUP BY t2.c_amount;
usr_id uniq_id increment usr2_id c_amount max
3 4 84676 NULL NULL NULL
SELECT t1.usr_id,t1.uniq_id,t1.increment,t2.usr2_id,t2.c_amount,t2.max FROM t1 LEFT JOIN t2 ON t2.id = t1.uniq_id WHERE t1.uniq_id = 4;
usr_id uniq_id increment usr2_id c_amount max
3 4 84676 NULL NULL NULL
drop table t1,t2;
CREATE TABLE t1 (
cod_asig int(11) DEFAULT '0' NOT NULL,
desc_larga_cat varchar(80) DEFAULT '' NOT NULL,
desc_larga_cas varchar(80) DEFAULT '' NOT NULL,
desc_corta_cat varchar(40) DEFAULT '' NOT NULL,
desc_corta_cas varchar(40) DEFAULT '' NOT NULL,
cred_total double(3,1) DEFAULT '0.0' NOT NULL,
pre_requisit int(11),
co_requisit int(11),
preco_requisit int(11),
PRIMARY KEY (cod_asig)
);
INSERT INTO t1 VALUES (10360,'asdfggfg','Introduccion a los Ordenadores I','asdfggfg','Introduccio Ordinadors I',6.0,NULL,NULL,NULL);
INSERT INTO t1 VALUES (10361,'Components i Circuits Electronics I','Componentes y Circuitos Electronicos I','Components i Circuits Electronics I','Comp. i Circ. Electr. I',6.0,NULL,NULL,NULL);
INSERT INTO t1 VALUES (10362,'Laboratori d`Ordinadors','Laboratorio de Ordenadores','Laboratori d`Ordinadors','Laboratori Ordinadors',4.5,NULL,NULL,NULL);
INSERT INTO t1 VALUES (10363,'Tecniques de Comunicacio Oral i Escrita','Tecnicas de Comunicacion Oral y Escrita','Tecniques de Comunicacio Oral i Escrita','Tec. Com. Oral i Escrita',4.5,NULL,NULL,NULL);
INSERT INTO t1 VALUES (11403,'Projecte Fi de Carrera','Proyecto Fin de Carrera','Projecte Fi de Carrera','PFC',9.0,NULL,NULL,NULL);
INSERT INTO t1 VALUES (11404,'+lgebra lineal','Algebra lineal','+lgebra lineal','+lgebra lineal',15.0,NULL,NULL,NULL);
INSERT INTO t1 VALUES (11405,'+lgebra lineal','Algebra lineal','+lgebra lineal','+lgebra lineal',18.0,NULL,NULL,NULL);
INSERT INTO t1 VALUES (11406,'Calcul Infinitesimal','Cßlculo Infinitesimal','Calcul Infinitesimal','Calcul Infinitesimal',15.0,NULL,NULL,NULL);
CREATE TABLE t2 (
idAssignatura int(11) DEFAULT '0' NOT NULL,
Grup int(11) DEFAULT '0' NOT NULL,
Places smallint(6) DEFAULT '0' NOT NULL,
PlacesOcupades int(11) DEFAULT '0',
PRIMARY KEY (idAssignatura,Grup)
);
INSERT INTO t2 VALUES (10360,12,333,0);
INSERT INTO t2 VALUES (10361,30,2,0);
INSERT INTO t2 VALUES (10361,40,3,0);
INSERT INTO t2 VALUES (10360,45,10,0);
INSERT INTO t2 VALUES (10362,10,12,0);
INSERT INTO t2 VALUES (10360,55,2,0);
INSERT INTO t2 VALUES (10360,70,0,0);
INSERT INTO t2 VALUES (10360,565656,0,0);
INSERT INTO t2 VALUES (10360,32767,7,0);
INSERT INTO t2 VALUES (10360,33,8,0);
INSERT INTO t2 VALUES (10360,7887,85,0);
INSERT INTO t2 VALUES (11405,88,8,0);
INSERT INTO t2 VALUES (10360,0,55,0);
INSERT INTO t2 VALUES (10360,99,0,0);
INSERT INTO t2 VALUES (11411,30,10,0);
INSERT INTO t2 VALUES (11404,0,0,0);
INSERT INTO t2 VALUES (10362,11,111,0);
INSERT INTO t2 VALUES (10363,33,333,0);
INSERT INTO t2 VALUES (11412,55,0,0);
INSERT INTO t2 VALUES (50003,66,6,0);
INSERT INTO t2 VALUES (11403,5,0,0);
INSERT INTO t2 VALUES (11406,11,11,0);
INSERT INTO t2 VALUES (11410,11410,131,0);
INSERT INTO t2 VALUES (11416,11416,32767,0);
INSERT INTO t2 VALUES (11409,0,0,0);
CREATE TABLE t3 (
id int(11) NOT NULL auto_increment,
dni_pasaporte char(16) DEFAULT '' NOT NULL,
idPla int(11) DEFAULT '0' NOT NULL,
cod_asig int(11) DEFAULT '0' NOT NULL,
any smallint(6) DEFAULT '0' NOT NULL,
quatrimestre smallint(6) DEFAULT '0' NOT NULL,
estat char(1) DEFAULT 'M' NOT NULL,
PRIMARY KEY (id),
UNIQUE dni_pasaporte (dni_pasaporte,idPla),
UNIQUE dni_pasaporte_2 (dni_pasaporte,idPla,cod_asig,any,quatrimestre)
);
INSERT INTO t3 VALUES (1,'11111111',1,10362,98,1,'M');
CREATE TABLE t4 (
id int(11) NOT NULL auto_increment,
papa int(11) DEFAULT '0' NOT NULL,
fill int(11) DEFAULT '0' NOT NULL,
idPla int(11) DEFAULT '0' NOT NULL,
PRIMARY KEY (id),
KEY papa (idPla,papa),
UNIQUE papa_2 (idPla,papa,fill)
);
INSERT INTO t4 VALUES (1,-1,10360,1);
INSERT INTO t4 VALUES (2,-1,10361,1);
INSERT INTO t4 VALUES (3,-1,10362,1);
SELECT DISTINCT fill,desc_larga_cat,cred_total,Grup,Places,PlacesOcupades FROM t4 LEFT JOIN t3 ON t3.cod_asig=fill AND estat='S' AND dni_pasaporte='11111111' AND t3.idPla=1 , t2,t1 WHERE fill=t1.cod_asig AND Places>PlacesOcupades AND fill=idAssignatura AND t4.idPla=1 AND papa=-1;
fill desc_larga_cat cred_total Grup Places PlacesOcupades
10360 asdfggfg 6.0 12 333 0
10361 Components i Circuits Electronics I 6.0 30 2 0
10361 Components i Circuits Electronics I 6.0 40 3 0
10360 asdfggfg 6.0 45 10 0
10362 Laboratori d`Ordinadors 4.5 10 12 0
10360 asdfggfg 6.0 55 2 0
10360 asdfggfg 6.0 32767 7 0
10360 asdfggfg 6.0 33 8 0
10360 asdfggfg 6.0 7887 85 0
10360 asdfggfg 6.0 0 55 0
10362 Laboratori d`Ordinadors 4.5 11 111 0
SELECT DISTINCT fill,t3.idPla FROM t4 LEFT JOIN t3 ON t3.cod_asig=t4.fill AND t3.estat='S' AND t3.dni_pasaporte='1234' AND t3.idPla=1 ;
fill idPla
10360 NULL
10361 NULL
10362 NULL
INSERT INTO t3 VALUES (3,'1234',1,10360,98,1,'S');
SELECT DISTINCT fill,t3.idPla FROM t4 LEFT JOIN t3 ON t3.cod_asig=t4.fill AND t3.estat='S' AND t3.dni_pasaporte='1234' AND t3.idPla=1 ;
fill idPla
10360 1
10361 NULL
10362 NULL
drop table t1,t2,t3,test.t4;
CREATE TABLE t1 (
id smallint(5) unsigned NOT NULL auto_increment,
name char(60) DEFAULT '' NOT NULL,
PRIMARY KEY (id)
);
INSERT INTO t1 VALUES (1,'Antonio Paz');
INSERT INTO t1 VALUES (2,'Lilliana Angelovska');
INSERT INTO t1 VALUES (3,'Thimble Smith');
CREATE TABLE t2 (
id smallint(5) unsigned NOT NULL auto_increment,
owner smallint(5) unsigned DEFAULT '0' NOT NULL,
name char(60),
PRIMARY KEY (id)
);
INSERT INTO t2 VALUES (1,1,'El Gato');
INSERT INTO t2 VALUES (2,1,'Perrito');
INSERT INTO t2 VALUES (3,3,'Happy');
select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner);
name name id
Antonio Paz El Gato 1
Antonio Paz Perrito 2
Lilliana Angelovska NULL NULL
Thimble Smith Happy 3
select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.id is null;
name name id
Lilliana Angelovska NULL NULL
explain select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.id is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where; Not exists; Using join buffer (Block Nested Loop)
explain select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.name is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (Block Nested Loop)
select count(*) from t1 left join t2 on (t1.id = t2.owner);
count(*)
4
select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner);
name name id
Antonio Paz El Gato 1
Antonio Paz Perrito 2
Lilliana Angelovska NULL NULL
Thimble Smith Happy 3
select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.id is null;
name name id
Lilliana Angelovska NULL NULL
explain select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.id is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where; Not exists; Using join buffer (Block Nested Loop)
explain select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.name is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (Block Nested Loop)
select count(*) from t2 right join t1 on (t1.id = t2.owner);
count(*)
4
select t1.name, t2.name, t2.id,t3.id from t2 right join t1 on (t1.id = t2.owner) left join t1 as t3 on t3.id=t2.owner;
name name id id
Antonio Paz El Gato 1 1
Antonio Paz Perrito 2 1
Lilliana Angelovska NULL NULL NULL
Thimble Smith Happy 3 3
select t1.name, t2.name, t2.id,t3.id from t1 right join t2 on (t1.id = t2.owner) right join t1 as t3 on t3.id=t2.owner;
name name id id
Antonio Paz El Gato 1 1
Antonio Paz Perrito 2 1
Thimble Smith Happy 3 3
NULL NULL NULL 2
select t1.name, t2.name, t2.id, t2.owner, t3.id from t1 left join t2 on (t1.id = t2.owner) right join t1 as t3 on t3.id=t2.owner;
name name id owner id
Antonio Paz El Gato 1 1 1
Antonio Paz Perrito 2 1 1
Thimble Smith Happy 3 3 3
NULL NULL NULL NULL 2
drop table t1,t2;
create table t1 (id int not null, str char(10), index(str));
insert into t1 values (1, null), (2, null), (3, "foo"), (4, "bar");
select * from t1 where str is not null order by id;
id str
3 foo
4 bar
select * from t1 where str is null;
id str
1 NULL
2 NULL
drop table t1;
CREATE TABLE t1 (
t1_id bigint(21) NOT NULL auto_increment,
PRIMARY KEY (t1_id)
);
CREATE TABLE t2 (
t2_id bigint(21) NOT NULL auto_increment,
PRIMARY KEY (t2_id)
);
CREATE TABLE t3 (
t3_id bigint(21) NOT NULL auto_increment,
PRIMARY KEY (t3_id)
);
CREATE TABLE t4 (
seq_0_id bigint(21) DEFAULT '0' NOT NULL,
seq_1_id bigint(21) DEFAULT '0' NOT NULL,
KEY seq_0_id (seq_0_id),
KEY seq_1_id (seq_1_id)
);
CREATE TABLE t5 (
seq_0_id bigint(21) DEFAULT '0' NOT NULL,
seq_1_id bigint(21) DEFAULT '0' NOT NULL,
KEY seq_1_id (seq_1_id),
KEY seq_0_id (seq_0_id)
);
insert into t1 values (1);
insert into t2 values (1);
insert into t3 values (1);
insert into t4 values (1,1);
insert into t5 values (1,1);
explain select * from t3 left join t4 on t4.seq_1_id = t2.t2_id left join t1 on t1.t1_id = t4.seq_0_id left join t5 on t5.seq_0_id = t1.t1_id left join t2 on t2.t2_id = t5.seq_1_id where t3.t3_id = 23;
ERROR 42S22: Unknown column 't2.t2_id' in 'on clause'
drop table t1,t2,t3,t4,t5;
create table t1 (n int, m int, o int, key(n));
create table t2 (n int not null, m int, o int, primary key(n));
insert into t1 values (1, 2, 11), (1, 2, 7), (2, 2, 8), (1,2,9),(1,3,9);
insert into t2 values (1, 2, 3),(2, 2, 8), (4,3,9),(3,2,10);
select t1.*, t2.* from t1 left join t2 on t1.n = t2.n and
t1.m = t2.m where t1.n = 1;
n m o n m o
1 2 11 1 2 3
1 2 7 1 2 3
1 2 9 1 2 3
1 3 9 NULL NULL NULL
select t1.*, t2.* from t1 left join t2 on t1.n = t2.n and
t1.m = t2.m where t1.n = 1 order by t1.o,t1.m;
n m o n m o
1 2 7 1 2 3
1 2 9 1 2 3
1 3 9 NULL NULL NULL
1 2 11 1 2 3
drop table t1,t2;
CREATE TABLE t1 (id1 INT NOT NULL PRIMARY KEY, dat1 CHAR(1), id2 INT);
INSERT INTO t1 VALUES (1,'a',1);
INSERT INTO t1 VALUES (2,'b',1);
INSERT INTO t1 VALUES (3,'c',2);
CREATE TABLE t2 (id2 INT NOT NULL PRIMARY KEY, dat2 CHAR(1));
INSERT INTO t2 VALUES (1,'x');
INSERT INTO t2 VALUES (2,'y');
INSERT INTO t2 VALUES (3,'z');
SELECT t2.id2 FROM t2 LEFT OUTER JOIN t1 ON t1.id2 = t2.id2 WHERE id1 IS NULL;
id2
3
SELECT t2.id2 FROM t2 NATURAL LEFT OUTER JOIN t1 WHERE id1 IS NULL;
id2
3
drop table t1,t2;
create table t1 ( color varchar(20), name varchar(20) );
insert into t1 values ( 'red', 'apple' );
insert into t1 values ( 'yellow', 'banana' );
insert into t1 values ( 'green', 'lime' );
insert into t1 values ( 'black', 'grape' );
insert into t1 values ( 'blue', 'blueberry' );
create table t2 ( count int, color varchar(20) );
insert into t2 values (10, 'green');
insert into t2 values (5, 'black');
insert into t2 values (15, 'white');
insert into t2 values (7, 'green');
select * from t1;
color name
red apple
yellow banana
green lime
black grape
blue blueberry
select * from t2;
count color
10 green
5 black
15 white
7 green
select * from t2 natural join t1;
color count name
green 10 lime
green 7 lime
black 5 grape
select t2.count, t1.name from t2 natural join t1;
count name
10 lime
7 lime
5 grape
select t2.count, t1.name from t2 inner join t1 using (color);
count name
10 lime
7 lime
5 grape
drop table t1;
drop table t2;
CREATE TABLE t1 (
pcode varchar(8) DEFAULT '' NOT NULL
);
INSERT INTO t1 VALUES ('kvw2000'),('kvw2001'),('kvw3000'),('kvw3001'),('kvw3002'),('kvw3500'),('kvw3501'),('kvw3502'),('kvw3800'),('kvw3801'),('kvw3802'),('kvw3900'),('kvw3901'),('kvw3902'),('kvw4000'),('kvw4001'),('kvw4002'),('kvw4200'),('kvw4500'),('kvw5000'),('kvw5001'),('kvw5500'),('kvw5510'),('kvw5600'),('kvw5601'),('kvw6000'),('klw1000'),('klw1020'),('klw1500'),('klw2000'),('klw2001'),('klw2002'),('kld2000'),('klw2500'),('kmw1000'),('kmw1500'),('kmw2000'),('kmw2001'),('kmw2100'),('kmw3000'),('kmw3200');
CREATE TABLE t2 (
pcode varchar(8) DEFAULT '' NOT NULL,
KEY pcode (pcode)
);
INSERT INTO t2 VALUES ('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw2000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3000'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw3500'),('kvw6000'),('kvw6000'),('kld2000');
SELECT t1.pcode, IF(ISNULL(t2.pcode), 0, COUNT(*)) AS count FROM t1
LEFT JOIN t2 ON t1.pcode = t2.pcode GROUP BY t1.pcode;
pcode count
kld2000 1
klw1000 0
klw1020 0
klw1500 0
klw2000 0
klw2001 0
klw2002 0
klw2500 0
kmw1000 0
kmw1500 0
kmw2000 0
kmw2001 0
kmw2100 0
kmw3000 0
kmw3200 0
kvw2000 26
kvw2001 0
kvw3000 36
kvw3001 0
kvw3002 0
kvw3500 26
kvw3501 0
kvw3502 0
kvw3800 0
kvw3801 0
kvw3802 0
kvw3900 0
kvw3901 0
kvw3902 0
kvw4000 0
kvw4001 0
kvw4002 0
kvw4200 0
kvw4500 0
kvw5000 0
kvw5001 0
kvw5500 0
kvw5510 0
kvw5600 0
kvw5601 0
kvw6000 2
SELECT SQL_BIG_RESULT t1.pcode, IF(ISNULL(t2.pcode), 0, COUNT(*)) AS count FROM t1 LEFT JOIN t2 ON t1.pcode = t2.pcode GROUP BY t1.pcode;
pcode count
kld2000 1
klw1000 0
klw1020 0
klw1500 0
klw2000 0
klw2001 0
klw2002 0
klw2500 0
kmw1000 0
kmw1500 0
kmw2000 0
kmw2001 0
kmw2100 0
kmw3000 0
kmw3200 0
kvw2000 26
kvw2001 0
kvw3000 36
kvw3001 0
kvw3002 0
kvw3500 26
kvw3501 0
kvw3502 0
kvw3800 0
kvw3801 0
kvw3802 0
kvw3900 0
kvw3901 0
kvw3902 0
kvw4000 0
kvw4001 0
kvw4002 0
kvw4200 0
kvw4500 0
kvw5000 0
kvw5001 0
kvw5500 0
kvw5510 0
kvw5600 0
kvw5601 0
kvw6000 2
drop table t1,t2;
CREATE TABLE t1 (
id int(11),
pid int(11),
rep_del tinyint(4),
KEY id (id),
KEY pid (pid)
);
INSERT INTO t1 VALUES (1,NULL,NULL);
INSERT INTO t1 VALUES (2,1,NULL);
select * from t1 LEFT JOIN t1 t2 ON (t1.id=t2.pid) AND t2.rep_del IS NULL;
id pid rep_del id pid rep_del
1 NULL NULL 2 1 NULL
2 1 NULL NULL NULL NULL
create index rep_del ON t1(rep_del);
select * from t1 LEFT JOIN t1 t2 ON (t1.id=t2.pid) AND t2.rep_del IS NULL;
id pid rep_del id pid rep_del
1 NULL NULL 2 1 NULL
2 1 NULL NULL NULL NULL
drop table t1;
CREATE TABLE t1 (
id int(11) DEFAULT '0' NOT NULL,
name tinytext DEFAULT '' NOT NULL,
UNIQUE id (id)
);
Warnings:
Warning 1101 BLOB/TEXT column 'name' can't have a default value
INSERT INTO t1 VALUES (1,'yes'),(2,'no');
CREATE TABLE t2 (
id int(11) DEFAULT '0' NOT NULL,
idx int(11) DEFAULT '0' NOT NULL,
UNIQUE id (id,idx)
);
INSERT INTO t2 VALUES (1,1);
explain SELECT * from t1 left join t2 on t1.id=t2.id where t2.id IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 NULL
1 SIMPLE t2 ref id id 4 test.t1.id 1 Using where; Not exists; Using index
SELECT * from t1 left join t2 on t1.id=t2.id where t2.id IS NULL;
id name id idx
2 no NULL NULL
drop table t1,t2;
create table t1 (bug_id mediumint, reporter mediumint);
create table t2 (bug_id mediumint, who mediumint, index(who));
insert into t2 values (1,1),(1,2);
insert into t1 values (1,1),(2,1);
SELECT * FROM t1 LEFT JOIN t2 ON (t1.bug_id = t2.bug_id AND t2.who = 2) WHERE (t1.reporter = 2 OR t2.who = 2);
bug_id reporter bug_id who
1 1 1 2
drop table t1,t2;
create table t1 (fooID smallint unsigned auto_increment, primary key (fooID));
create table t2 (fooID smallint unsigned not null, barID smallint unsigned not null, primary key (fooID,barID));
insert into t1 (fooID) values (10),(20),(30);
insert into t2 values (10,1),(20,2),(30,3);
explain select * from t2 left join t1 on t1.fooID = t2.fooID and t1.fooID = 30;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL PRIMARY 4 NULL 3 Using index
1 SIMPLE t1 const PRIMARY PRIMARY 2 const 1 Using where; Using index
select * from t2 left join t1 on t1.fooID = t2.fooID and t1.fooID = 30;
fooID barID fooID
10 1 NULL
20 2 NULL
30 3 30
select * from t2 left join t1 ignore index(primary) on t1.fooID = t2.fooID and t1.fooID = 30;
fooID barID fooID
10 1 NULL
20 2 NULL
30 3 30
drop table t1,t2;
create table t1 (i int);
create table t2 (i int);
create table t3 (i int);
insert into t1 values(1),(2);
insert into t2 values(2),(3);
insert into t3 values(2),(4);
select * from t1 natural left join t2 natural left join t3;
i
1
2
select * from t1 natural left join t2 where (t2.i is not null)=0;
i
1
select * from t1 natural left join t2 where (t2.i is not null) is not null;
i
1
2
select * from t1 natural left join t2 where (i is not null)=0;
i
select * from t1 natural left join t2 where (i is not null) is not null;
i
1
2
drop table t1,t2,t3;
create table t1 (f1 integer,f2 integer,f3 integer);
create table t2 (f2 integer,f4 integer);
create table t3 (f3 integer,f5 integer);
select * from t1
left outer join t2 using (f2)
left outer join t3 using (f3);
f3 f2 f1 f4 f5
drop table t1,t2,t3;
create table t1 (a1 int, a2 int);
create table t2 (b1 int not null, b2 int);
create table t3 (c1 int, c2 int);
insert into t1 values (1,2), (2,2), (3,2);
insert into t2 values (1,3), (2,3);
insert into t3 values (2,4), (3,4);
select * from t1 left join t2 on b1 = a1 left join t3 on c1 = a1 and b1 is null;
a1 a2 b1 b2 c1 c2
1 2 1 3 NULL NULL
2 2 2 3 NULL NULL
3 2 NULL NULL 3 4
explain select * from t1 left join t2 on b1 = a1 left join t3 on c1 = a1 and b1 is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
drop table t1, t2, t3;
create table t1 (
a int(11),
b char(10),
key (a)
);
insert into t1 (a) values (1),(2),(3),(4);
create table t2 (a int);
select * from t1 left join t2 on t1.a=t2.a where not (t2.a <=> t1.a);
a b a
1 NULL NULL
2 NULL NULL
3 NULL NULL
4 NULL NULL
select * from t1 left join t2 on t1.a=t2.a having not (t2.a <=> t1.a);
a b a
1 NULL NULL
2 NULL NULL
3 NULL NULL
4 NULL NULL
drop table t1,t2;
create table t1 (
match_id tinyint(3) unsigned not null auto_increment,
home tinyint(3) unsigned default '0',
unique key match_id (match_id),
key match_id_2 (match_id)
);
insert into t1 values("1", "2");
create table t2 (
player_id tinyint(3) unsigned default '0',
match_1_h tinyint(3) unsigned default '0',
key player_id (player_id)
);
insert into t2 values("1", "5");
insert into t2 values("2", "9");
insert into t2 values("3", "3");
insert into t2 values("4", "7");
insert into t2 values("5", "6");
insert into t2 values("6", "8");
insert into t2 values("7", "4");
insert into t2 values("8", "12");
insert into t2 values("9", "11");
insert into t2 values("10", "10");
explain select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
(t2 s left join t1 m on m.match_id = 1)
order by m.match_id desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE s ALL NULL NULL NULL NULL 10 Using temporary; Using filesort
1 SIMPLE m const match_id,match_id_2 match_id 1 const 1 Using join buffer (Batched Key Access)
explain select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
(t2 s left join t1 m on m.match_id = 1)
order by UUX desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE s ALL NULL NULL NULL NULL 10 Using temporary; Using filesort
1 SIMPLE m const match_id,match_id_2 match_id 1 const 1 Using join buffer (Batched Key Access)
select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
(t2 s left join t1 m on m.match_id = 1)
order by UUX desc;
player_id match_1_h * match_id home UUX
8 12 * 1 2 10
9 11 * 1 2 9
10 10 * 1 2 8
2 9 * 1 2 7
6 8 * 1 2 6
4 7 * 1 2 5
5 6 * 1 2 4
1 5 * 1 2 3
7 4 * 1 2 2
3 3 * 1 2 1
explain select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
t2 s straight_join t1 m where m.match_id = 1
order by UUX desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE s ALL NULL NULL NULL NULL 10 Using temporary; Using filesort
1 SIMPLE m const match_id,match_id_2 match_id 1 const 1 Using join buffer (Batched Key Access)
select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
t2 s straight_join t1 m where m.match_id = 1
order by UUX desc;
player_id match_1_h * match_id home UUX
8 12 * 1 2 10
9 11 * 1 2 9
10 10 * 1 2 8
2 9 * 1 2 7
6 8 * 1 2 6
4 7 * 1 2 5
5 6 * 1 2 4
1 5 * 1 2 3
7 4 * 1 2 2
3 3 * 1 2 1
drop table t1, t2;
create table t1 (a int, b int, unique index idx (a, b));
create table t2 (a int, b int, c int, unique index idx (a, b));
insert into t1 values (1, 10), (1,11), (2,10), (2,11);
insert into t2 values (1,10,3);
select t1.a, t1.b, t2.c from t1 left join t2
on t1.a=t2.a and t1.b=t2.b and t2.c=3
where t1.a=1 and t2.c is null;
a b c
1 11 NULL
drop table t1, t2;
CREATE TABLE t1 (
ts_id bigint(20) default NULL,
inst_id tinyint(4) default NULL,
flag_name varchar(64) default NULL,
flag_value text,
UNIQUE KEY ts_id (ts_id,inst_id,flag_name)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE t2 (
ts_id bigint(20) default NULL,
inst_id tinyint(4) default NULL,
flag_name varchar(64) default NULL,
flag_value text,
UNIQUE KEY ts_id (ts_id,inst_id,flag_name)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
INSERT INTO t1 VALUES
(111056548820001, 0, 'flag1', NULL),
(111056548820001, 0, 'flag2', NULL),
(2, 0, 'other_flag', NULL);
INSERT INTO t2 VALUES
(111056548820001, 3, 'flag1', 'sss');
SELECT t1.flag_name,t2.flag_value
FROM t1 LEFT JOIN t2
ON (t1.ts_id = t2.ts_id AND t1.flag_name = t2.flag_name AND
t2.inst_id = 3)
WHERE t1.inst_id = 0 AND t1.ts_id=111056548820001 AND
t2.flag_value IS NULL;
flag_name flag_value
flag2 NULL
DROP TABLE t1,t2;
CREATE TABLE t1 (
id int(11) unsigned NOT NULL auto_increment,
text_id int(10) unsigned default NULL,
PRIMARY KEY (id)
);
INSERT INTO t1 VALUES("1", "0");
INSERT INTO t1 VALUES("2", "10");
CREATE TABLE t2 (
text_id char(3) NOT NULL default '',
language_id char(3) NOT NULL default '',
text_data text,
PRIMARY KEY (text_id,language_id)
);
INSERT INTO t2 VALUES("0", "EN", "0-EN");
INSERT INTO t2 VALUES("0", "SV", "0-SV");
INSERT INTO t2 VALUES("10", "EN", "10-EN");
INSERT INTO t2 VALUES("10", "SV", "10-SV");
SELECT t1.id, t1.text_id, t2.text_data
FROM t1 LEFT JOIN t2
ON t1.text_id = t2.text_id
AND t2.language_id = 'SV'
WHERE (t1.id LIKE '%' OR t2.text_data LIKE '%');
id text_id text_data
1 0 0-SV
2 10 10-SV
DROP TABLE t1, t2;
CREATE TABLE t0 (a0 int PRIMARY KEY);
CREATE TABLE t1 (a1 int PRIMARY KEY);
CREATE TABLE t2 (a2 int);
CREATE TABLE t3 (a3 int);
INSERT INTO t0 VALUES (1);
INSERT INTO t1 VALUES (1);
INSERT INTO t2 VALUES (1), (2);
INSERT INTO t3 VALUES (1), (2);
SELECT * FROM t1 LEFT JOIN t2 ON a1=0;
a1 a2
1 NULL
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON a1=0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where
SELECT * FROM t1 LEFT JOIN (t2,t3) ON a1=0;
a1 a2 a3
1 NULL NULL
EXPLAIN SELECT * FROM t1 LEFT JOIN (t2,t3) ON a1=0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 NULL
SELECT * FROM t0, t1 LEFT JOIN (t2,t3) ON a1=0 WHERE a0=a1;
a0 a1 a2 a3
1 1 NULL NULL
EXPLAIN SELECT * FROM t0, t1 LEFT JOIN (t2,t3) ON a1=0 WHERE a0=a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 system PRIMARY NULL NULL NULL 1 NULL
1 SIMPLE t1 system PRIMARY NULL NULL NULL 1 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 NULL
INSERT INTO t0 VALUES (0);
INSERT INTO t1 VALUES (0);
SELECT * FROM t0, t1 LEFT JOIN (t2,t3) ON a1=5 WHERE a0=a1 AND a0=1;
a0 a1 a2 a3
1 1 NULL NULL
EXPLAIN SELECT * FROM t0, t1 LEFT JOIN (t2,t3) ON a1=5 WHERE a0=a1 AND a0=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 const PRIMARY PRIMARY 4 const 1 Using index
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 Using index
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 NULL
drop table t1,t2;
create table t1 (a int, b int);
insert into t1 values (1,1),(2,2),(3,3);
create table t2 (a int, b int);
insert into t2 values (1,1), (2,2);
select * from t2 right join t1 on t2.a=t1.a;
a b a b
1 1 1 1
2 2 2 2
NULL NULL 3 3
select straight_join * from t2 right join t1 on t2.a=t1.a;
a b a b
1 1 1 1
2 2 2 2
NULL NULL 3 3
DROP TABLE t0,t1,t2,t3;
CREATE TABLE t1 (a int PRIMARY KEY, b int);
CREATE TABLE t2 (a int PRIMARY KEY, b int);
INSERT INTO t1 VALUES (1,1), (2,1), (3,1), (4,2);
INSERT INTO t2 VALUES (1,2), (2,2);
SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.a;
a b a b
1 1 1 2
2 1 2 2
3 1 NULL NULL
4 2 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.a WHERE t1.b=1;
a b a b
1 1 1 2
2 1 2 2
3 1 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.a
WHERE t1.b=1 XOR (NOT ISNULL(t2.a) AND t2.b=1);
a b a b
1 1 1 2
2 1 2 2
3 1 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.a WHERE not(0+(t1.a=30 and t2.b=1));
a b a b
1 1 1 2
2 1 2 2
3 1 NULL NULL
4 2 NULL NULL
DROP TABLE t1,t2;
set group_concat_max_len=5;
create table t1 (a int, b varchar(20));
create table t2 (a int, c varchar(20));
insert into t1 values (1,"aaaaaaaaaa"),(2,"bbbbbbbbbb");
insert into t2 values (1,"cccccccccc"),(2,"dddddddddd");
select group_concat(t1.b,t2.c) from t1 left join t2 using(a) group by t1.a;
group_concat(t1.b,t2.c)
aaaaa
bbbbb
Warnings:
Warning 1260 Row 1 was cut by GROUP_CONCAT()
Warning 1260 Row 2 was cut by GROUP_CONCAT()
select group_concat(t1.b,t2.c) from t1 inner join t2 using(a) group by t1.a;
group_concat(t1.b,t2.c)
aaaaa
bbbbb
Warnings:
Warning 1260 Row 1 was cut by GROUP_CONCAT()
Warning 1260 Row 2 was cut by GROUP_CONCAT()
select group_concat(t1.b,t2.c) from t1 left join t2 using(a) group by a;
group_concat(t1.b,t2.c)
aaaaa
bbbbb
Warnings:
Warning 1260 Row 1 was cut by GROUP_CONCAT()
Warning 1260 Row 2 was cut by GROUP_CONCAT()
select group_concat(t1.b,t2.c) from t1 inner join t2 using(a) group by a;
group_concat(t1.b,t2.c)
aaaaa
bbbbb
Warnings:
Warning 1260 Row 1 was cut by GROUP_CONCAT()
Warning 1260 Row 2 was cut by GROUP_CONCAT()
drop table t1, t2;
set group_concat_max_len=default;
create table t1 (gid smallint(5) unsigned not null, x int(11) not null, y int(11) not null, art int(11) not null, primary key (gid,x,y));
insert t1 values (1, -5, -8, 2), (1, 2, 2, 1), (1, 1, 1, 1);
create table t2 (gid smallint(5) unsigned not null, x int(11) not null, y int(11) not null, id int(11) not null, primary key (gid,id,x,y), key id (id));
insert t2 values (1, -5, -8, 1), (1, 1, 1, 1), (1, 2, 2, 1);
create table t3 ( set_id smallint(5) unsigned not null, id tinyint(4) unsigned not null, name char(12) not null, primary key (id,set_id));
insert t3 values (0, 1, 'a'), (1, 1, 'b'), (0, 2, 'c'), (1, 2, 'd'), (1, 3, 'e'), (1, 4, 'f'), (1, 5, 'g'), (1, 6, 'h');
explain select name from t1 left join t2 on t1.x = t2.x and t1.y = t2.y
left join t3 on t1.art = t3.id where t2.id =1 and t2.x = -5 and t2.y =-8
and t1.gid =1 and t2.gid =1 and t3.set_id =1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 10 const,const,const 1 NULL
1 SIMPLE t2 const PRIMARY,id PRIMARY 14 const,const,const,const 1 Using index
1 SIMPLE t3 const PRIMARY PRIMARY 3 const,const 1 NULL
drop tables t1,t2,t3;
CREATE TABLE t1 (EMPNUM INT, GRP INT);
INSERT INTO t1 VALUES (0, 10);
INSERT INTO t1 VALUES (2, 30);
CREATE TABLE t2 (EMPNUM INT, NAME CHAR(5));
INSERT INTO t2 VALUES (0, 'KERI');
INSERT INTO t2 VALUES (9, 'BARRY');
CREATE VIEW v1 AS
SELECT COALESCE(t2.EMPNUM,t1.EMPNUM) AS EMPNUM, NAME, GRP
FROM t2 LEFT OUTER JOIN t1 ON t2.EMPNUM=t1.EMPNUM;
SELECT * FROM v1;
EMPNUM NAME GRP
0 KERI 10
9 BARRY NULL
SELECT * FROM v1 WHERE EMPNUM < 10;
EMPNUM NAME GRP
0 KERI 10
9 BARRY NULL
DROP VIEW v1;
DROP TABLE t1,t2;
CREATE TABLE t1 (c11 int);
CREATE TABLE t2 (c21 int);
INSERT INTO t1 VALUES (30), (40), (50);
INSERT INTO t2 VALUES (300), (400), (500);
SELECT * FROM t1 LEFT JOIN t2 ON (c11=c21 AND c21=30) WHERE c11=40;
c11 c21
40 NULL
DROP TABLE t1, t2;
CREATE TABLE t1 (a int PRIMARY KEY, b int);
CREATE TABLE t2 (a int PRIMARY KEY, b int);
INSERT INTO t1 VALUES (1,2), (2,1), (3,2), (4,3), (5,6), (6,5), (7,8), (8,7), (9,10);
INSERT INTO t2 VALUES (3,0), (4,1), (6,4), (7,5);
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t2.b <= t1.a AND t1.a <= t1.b;
a b a b
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a BETWEEN t2.b AND t1.b;
a b a b
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t1.a NOT BETWEEN t2.b AND t1.b);
a b a b
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t2.b > t1.a OR t1.a > t1.b;
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
2 1 NULL NULL
8 7 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a NOT BETWEEN t2.b AND t1.b;
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
2 1 NULL NULL
8 7 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t1.a BETWEEN t2.b AND t1.b);
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
2 1 NULL NULL
8 7 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a = t2.a OR t2.b > t1.a OR t1.a > t1.b;
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
2 1 NULL NULL
8 7 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t1.a != t2.a AND t1.a BETWEEN t2.b AND t1.b);
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
2 1 NULL NULL
8 7 NULL NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a = t2.a AND (t2.b > t1.a OR t1.a > t1.b);
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t1.a != t2.a OR t1.a BETWEEN t2.b AND t1.b);
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a = t2.a OR t1.a = t2.b;
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a IN(t2.a, t2.b);
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t1.a NOT IN(t2.a, t2.b));
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a != t1.b AND t1.a != t2.b;
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a NOT IN(t1.b, t2.b);
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t1.a IN(t1.b, t2.b));
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t2.a != t2.b OR (t1.a != t2.a AND t1.a != t2.b);
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t2.a = t2.b AND t1.a IN(t2.a, t2.b));
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t2.a != t2.b AND t1.a != t1.b AND t1.a != t2.b;
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE NOT(t2.a = t2.b OR t1.a IN(t1.b, t2.b));
a b a b
3 2 3 0
4 3 4 1
6 5 6 4
7 8 7 5
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a = t2.a OR t1.a = t2.b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL PRIMARY NULL NULL NULL 4 Using where
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.a 1 Using join buffer (Batched Key Access)
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a IN(t2.a, t2.b);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL PRIMARY NULL NULL NULL 4 Using where
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.a 1 Using join buffer (Batched Key Access)
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a > IF(t1.a = t2.b-2, t2.b, t2.b-1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL PRIMARY NULL NULL NULL 4 Using where
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.a 1 Using join buffer (Batched Key Access)
DROP TABLE t1,t2;
DROP VIEW IF EXISTS v1,v2;
DROP TABLE IF EXISTS t1,t2;
CREATE TABLE t1 (a int);
CREATE table t2 (b int);
INSERT INTO t1 VALUES (1), (2), (3), (4), (1), (1), (3);
INSERT INTO t2 VALUES (2), (3);
CREATE VIEW v1 AS SELECT a FROM t1 JOIN t2 ON t1.a=t2.b;
CREATE VIEW v2 AS SELECT b FROM t2 JOIN t1 ON t2.b=t1.a;
SELECT v1.a, v2. b
FROM v1 LEFT OUTER JOIN v2 ON (v1.a=v2.b) AND (v1.a >= 3)
GROUP BY v1.a;
a b
2 NULL
3 3
SELECT v1.a, v2. b
FROM { OJ v1 LEFT OUTER JOIN v2 ON (v1.a=v2.b) AND (v1.a >= 3) }
GROUP BY v1.a;
a b
2 NULL
3 3
DROP VIEW v1,v2;
DROP TABLE t1,t2;
CREATE TABLE t1 (a int);
CREATE TABLE t2 (b int);
INSERT INTO t1 VALUES (1), (2), (3), (4);
INSERT INTO t2 VALUES (2), (3);
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.b WHERE (1=1);
a b
1 NULL
2 2
3 3
4 NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.b WHERE (1 OR 1);
a b
1 NULL
2 2
3 3
4 NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.b WHERE (0 OR 1);
a b
1 NULL
2 2
3 3
4 NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.b WHERE (1=1 OR 2=2);
a b
1 NULL
2 2
3 3
4 NULL
SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.b WHERE (1=1 OR 1=0);
a b
1 NULL
2 2
3 3
4 NULL
DROP TABLE t1,t2;
CREATE TABLE t1 (
f1 varchar(16) collate latin1_swedish_ci PRIMARY KEY,
f2 varchar(16) collate latin1_swedish_ci
);
CREATE TABLE t2 (
f1 varchar(16) collate latin1_swedish_ci PRIMARY KEY,
f3 varchar(16) collate latin1_swedish_ci
);
INSERT INTO t1 VALUES ('bla','blah');
INSERT INTO t2 VALUES ('bla','sheep');
SELECT * FROM t1 JOIN t2 USING(f1) WHERE f1='Bla';
f1 f2 f3
bla blah sheep
SELECT * FROM t1 LEFT JOIN t2 USING(f1) WHERE f1='bla';
f1 f2 f3
bla blah sheep
SELECT * FROM t1 LEFT JOIN t2 USING(f1) WHERE f1='Bla';
f1 f2 f3
bla blah sheep
DROP TABLE t1,t2;
CREATE TABLE t1 (id int PRIMARY KEY, a varchar(8));
CREATE TABLE t2 (id int NOT NULL, b int NOT NULL, INDEX idx(id));
INSERT INTO t1 VALUES
(1,'aaaaaaa'), (5,'eeeeeee'), (4,'ddddddd'), (2,'bbbbbbb'), (3,'ccccccc');
INSERT INTO t2 VALUES
(3,10), (2,20), (5,30), (3,20), (5,10), (3,40), (3,30), (2,10), (2,40);
EXPLAIN
SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 NULL
1 SIMPLE t2 ALL idx NULL NULL NULL 9 Using where; Not exists; Using join buffer (Block Nested Loop)
flush status;
SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL;
id a
1 aaaaaaa
4 ddddddd
show status like 'Handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 0
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_next 16
DROP TABLE t1,t2;
CREATE TABLE t1 (c int PRIMARY KEY, e int NOT NULL);
INSERT INTO t1 VALUES (1,0), (2,1);
CREATE TABLE t2 (d int PRIMARY KEY);
INSERT INTO t2 VALUES (1), (2), (3);
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 NULL
1 SIMPLE t2 index NULL PRIMARY 4 NULL 3 Using where; Not exists; Using index
SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
c e d
1 0 NULL
SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL;
c e d
1 0 NULL
DROP TABLE t1,t2;
#
# Bug#47650: using group by with rollup without indexes returns incorrect
# results with where
#
CREATE TABLE t1 ( a INT );
INSERT INTO t1 VALUES (1);
CREATE TABLE t2 ( a INT, b INT );
INSERT INTO t2 VALUES (1, 1),(1, 2),(1, 3),(2, 4),(2, 5);
EXPLAIN
SELECT t1.a, COUNT( t2.b ), SUM( t2.b ), MAX( t2.b )
FROM t1 LEFT JOIN t2 USING( a )
GROUP BY t1.a WITH ROLLUP;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 Using temporary; Using filesort
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 Using where
SELECT t1.a, COUNT( t2.b ), SUM( t2.b ), MAX( t2.b )
FROM t1 LEFT JOIN t2 USING( a )
GROUP BY t1.a WITH ROLLUP;
a COUNT( t2.b ) SUM( t2.b ) MAX( t2.b )
1 3 6 3
NULL 3 6 3
EXPLAIN
SELECT t1.a, COUNT( t2.b ), SUM( t2.b ), MAX( t2.b )
FROM t1 JOIN t2 USING( a )
GROUP BY t1.a WITH ROLLUP;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 Using filesort
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 Using where
SELECT t1.a, COUNT( t2.b ), SUM( t2.b ), MAX( t2.b )
FROM t1 JOIN t2 USING( a )
GROUP BY t1.a WITH ROLLUP;
a COUNT( t2.b ) SUM( t2.b ) MAX( t2.b )
1 3 6 3
NULL 3 6 3
DROP TABLE t1, t2;
#
# Bug#51598 Inconsistent behaviour with a COALESCE statement inside an IN comparison
#
CREATE TABLE t1(f1 INT, f2 INT, f3 INT);
INSERT INTO t1 VALUES (1, NULL, 3);
CREATE TABLE t2(f1 INT, f2 INT);
INSERT INTO t2 VALUES (2, 1);
EXPLAIN EXTENDED SELECT * FROM t1 LEFT JOIN t2 ON t1.f2 = t2.f2
WHERE (COALESCE(t1.f1, t2.f1), f3) IN ((1, 3), (2, 2));
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00 NULL
1 SIMPLE t2 system NULL NULL NULL NULL 1 100.00 NULL
Warnings:
Note 1003 /* select#1 */ select '1' AS `f1`,NULL AS `f2`,'3' AS `f3`,NULL AS `f1`,NULL AS `f2` from `test`.`t2` where ((coalesce('1',NULL),'3') in ((1,3),(2,2)))
SELECT * FROM t1 LEFT JOIN t2 ON t1.f2 = t2.f2
WHERE (COALESCE(t1.f1, t2.f1), f3) IN ((1, 3), (2, 2));
f1 f2 f3 f1 f2
1 NULL 3 NULL NULL
DROP TABLE t1, t2;
#
# Bug#52357: Assertion failed: join->best_read in greedy_search
# optimizer_search_depth=0
#
CREATE TABLE t1( a INT );
INSERT INTO t1 VALUES (1),(2);
SET optimizer_search_depth = 0;
# Should not core dump on query preparation
EXPLAIN
SELECT 1
FROM t1 tt3 LEFT OUTER JOIN t1 tt4 ON 1
LEFT OUTER JOIN t1 tt5 ON 1
LEFT OUTER JOIN t1 tt6 ON 1
LEFT OUTER JOIN t1 tt7 ON 1
LEFT OUTER JOIN t1 tt8 ON 1
RIGHT OUTER JOIN t1 tt2 ON 1
RIGHT OUTER JOIN t1 tt1 ON 1
STRAIGHT_JOIN t1 tt9 ON 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE tt1 ALL NULL NULL NULL NULL 2 NULL
1 SIMPLE tt2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE tt3 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE tt4 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE tt5 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE tt6 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE tt7 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE tt8 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE tt9 ALL NULL NULL NULL NULL 2 Using join buffer (Block Nested Loop)
SET optimizer_search_depth = DEFAULT;
DROP TABLE t1;
#
# Bug#46091 STRAIGHT_JOIN + RIGHT JOIN returns different result
#
CREATE TABLE t1 (f1 INT NOT NULL);
INSERT INTO t1 VALUES (9),(0);
CREATE TABLE t2 (f1 INT NOT NULL);
INSERT INTO t2 VALUES
(5),(3),(0),(3),(1),(0),(1),(7),(1),(0),(0),(8),(4),(9),(0),(2),(0),(8),(5),(1);
SELECT STRAIGHT_JOIN COUNT(*) FROM t1 TA1
RIGHT JOIN t2 TA2 JOIN t2 TA3 ON TA2.f1 ON TA3.f1;
COUNT(*)
476
EXPLAIN SELECT STRAIGHT_JOIN COUNT(*) FROM t1 TA1
RIGHT JOIN t2 TA2 JOIN t2 TA3 ON TA2.f1 ON TA3.f1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE TA2 ALL NULL NULL NULL NULL 20 Using where
1 SIMPLE TA3 ALL NULL NULL NULL NULL 20 Using join buffer (Block Nested Loop)
1 SIMPLE TA1 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (Block Nested Loop)
DROP TABLE t1, t2;
#
# Bug#48971 Segfault in add_found_match_trig_cond () at sql_select.cc:5990
#
CREATE TABLE t1(f1 INT, PRIMARY KEY (f1));
INSERT INTO t1 VALUES (1),(2);
EXPLAIN EXTENDED SELECT STRAIGHT_JOIN jt1.f1 FROM t1 AS jt1
LEFT JOIN t1 AS jt2
RIGHT JOIN t1 AS jt3
JOIN t1 AS jt4 ON 1
LEFT JOIN t1 AS jt5 ON 1
ON 1
RIGHT JOIN t1 AS jt6 ON jt6.f1
ON 1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE jt1 index NULL PRIMARY 4 NULL 2 100.00 Using index
1 SIMPLE jt6 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt3 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt4 index NULL PRIMARY 4 NULL 2 100.00 Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt5 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt2 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select straight_join `test`.`jt1`.`f1` AS `f1` from `test`.`t1` `jt1` left join (`test`.`t1` `jt6` left join (`test`.`t1` `jt3` join `test`.`t1` `jt4` left join `test`.`t1` `jt5` on(1) left join `test`.`t1` `jt2` on(1)) on((`test`.`jt6`.`f1` and 1))) on(1) where 1
EXPLAIN EXTENDED SELECT STRAIGHT_JOIN jt1.f1 FROM t1 AS jt1
RIGHT JOIN t1 AS jt2
RIGHT JOIN t1 AS jt3
JOIN t1 AS jt4 ON 1
LEFT JOIN t1 AS jt5 ON 1
ON 1
RIGHT JOIN t1 AS jt6 ON jt6.f1
ON 1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE jt6 index NULL PRIMARY 4 NULL 2 100.00 Using index
1 SIMPLE jt3 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt4 index NULL PRIMARY 4 NULL 2 100.00 Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt5 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt2 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
1 SIMPLE jt1 index NULL PRIMARY 4 NULL 2 100.00 Using where; Using index; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select straight_join `test`.`jt1`.`f1` AS `f1` from `test`.`t1` `jt6` left join (`test`.`t1` `jt3` join `test`.`t1` `jt4` left join `test`.`t1` `jt5` on(1) left join `test`.`t1` `jt2` on(1)) on((`test`.`jt6`.`f1` and 1)) left join `test`.`t1` `jt1` on(1) where 1
DROP TABLE t1;
#
# Bug#57688 Assertion `!table || (!table->write_set || bitmap_is_set(table->write_set, field
#
CREATE TABLE t1 (f1 INT NOT NULL, PRIMARY KEY (f1));
CREATE TABLE t2 (f1 INT NOT NULL, f2 INT NOT NULL, PRIMARY KEY (f1, f2));
INSERT INTO t1 VALUES (4);
INSERT INTO t2 VALUES (3, 3);
INSERT INTO t2 VALUES (7, 7);
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t2.f1 = t1.f1
WHERE t1.f1 = 4
GROUP BY t2.f1, t2.f2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system PRIMARY NULL NULL NULL 1 Using temporary; Using filesort
1 SIMPLE t2 ref PRIMARY PRIMARY 4 const 1 Using index
SELECT * FROM t1 LEFT JOIN t2 ON t2.f1 = t1.f1
WHERE t1.f1 = 4
GROUP BY t2.f1, t2.f2;
f1 f1 f2
4 NULL NULL
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t2.f1 = t1.f1
WHERE t1.f1 = 4 AND t2.f1 IS NOT NULL AND t2.f2 IS NOT NULL
GROUP BY t2.f1, t2.f2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system PRIMARY NULL NULL NULL 1 Using filesort
1 SIMPLE t2 ref PRIMARY PRIMARY 4 const 1 Using where; Using index
SELECT * FROM t1 LEFT JOIN t2 ON t2.f1 = t1.f1
WHERE t1.f1 = 4 AND t2.f1 IS NOT NULL AND t2.f2 IS NOT NULL
GROUP BY t2.f1, t2.f2;
f1 f1 f2
DROP TABLE t1,t2;
#
# Bug#57034 incorrect OUTER JOIN result when joined on unique key
#
CREATE TABLE t1 (pk INT PRIMARY KEY,
col_int INT,
col_int_unique INT UNIQUE KEY);
INSERT INTO t1 VALUES (1,NULL,2), (2,0,0);
CREATE TABLE t2 (pk INT PRIMARY KEY,
col_int INT,
col_int_unique INT UNIQUE KEY);
INSERT INTO t2 VALUES (1,0,1), (2,0,2);
EXPLAIN
SELECT * FROM t1 LEFT JOIN t2
ON t1.col_int_unique = t2.col_int_unique AND t1.col_int = t2.col_int
WHERE t1.pk=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 NULL
1 SIMPLE t2 const col_int_unique col_int_unique 5 const 1 NULL
SELECT * FROM t1 LEFT JOIN t2
ON t1.col_int_unique = t2.col_int_unique AND t1.col_int = t2.col_int
WHERE t1.pk=1;
pk col_int col_int_unique pk col_int col_int_unique
1 NULL 2 NULL NULL NULL
DROP TABLE t1,t2;
#
# Bug#48046 Server incorrectly processing JOINs on NULL values
#
CREATE TABLE `BB` (
`pk` int(11) NOT NULL AUTO_INCREMENT,
`time_key` time DEFAULT NULL,
`varchar_key` varchar(1) DEFAULT NULL,
`varchar_nokey` varchar(1) DEFAULT NULL,
PRIMARY KEY (`pk`),
KEY `time_key` (`time_key`),
KEY `varchar_key` (`varchar_key`)
) ENGINE=MyISAM AUTO_INCREMENT=11 DEFAULT CHARSET=latin1;
INSERT INTO `BB` VALUES (10,'18:27:58',NULL,NULL);
SELECT table1.time_key AS field1, table2.pk
FROM BB table1 LEFT JOIN BB table2
ON table2.varchar_nokey = table1.varchar_key
HAVING field1;
field1 pk
18:27:58 NULL
DROP TABLE BB;
#
# Bug#49600 Server incorrectly processing RIGHT JOIN with
# constant WHERE clause and no index
#
CREATE TABLE `BB` (
`col_datetime_key` datetime DEFAULT NULL,
`col_varchar_key` varchar(1) DEFAULT NULL,
`col_varchar_nokey` varchar(1) DEFAULT NULL,
KEY `col_datetime_key` (`col_datetime_key`),
KEY `col_varchar_key` (`col_varchar_key`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
INSERT INTO `BB` VALUES ('1900-01-01 00:00:00',NULL,NULL);
SELECT table1.col_datetime_key
FROM BB table1 RIGHT JOIN BB table2
ON table2 .col_varchar_nokey = table1.col_varchar_key
WHERE 7;
col_datetime_key
NULL
ALTER TABLE BB DISABLE KEYS;
SELECT table1.col_datetime_key
FROM BB table1 RIGHT JOIN BB table2
ON table2 .col_varchar_nokey = table1.col_varchar_key
WHERE 7;
col_datetime_key
NULL
DROP TABLE BB;
#
# Bug#58490: Incorrect result in multi level OUTER JOIN
# in combination with IS NULL
#
CREATE TABLE t1 (i INT NOT NULL);
INSERT INTO t1 VALUES (0), (2),(3),(4);
CREATE TABLE t2 (i INT NOT NULL);
INSERT INTO t2 VALUES (0),(1), (3),(4);
CREATE TABLE t3 (i INT NOT NULL);
INSERT INTO t3 VALUES (0),(1),(2), (4);
CREATE TABLE t4 (i INT NOT NULL);
INSERT INTO t4 VALUES (0),(1),(2),(3) ;
SELECT * FROM
t1 LEFT JOIN
( t2 LEFT JOIN
( t3 LEFT JOIN
t4
ON t4.i = t3.i
)
ON t3.i = t2.i
)
ON t2.i = t1.i
;
i i i i
0 0 0 0
2 NULL NULL NULL
3 3 NULL NULL
4 4 4 NULL
SELECT * FROM
t1 LEFT JOIN
( t2 LEFT JOIN
( t3 LEFT JOIN
t4
ON t4.i = t3.i
)
ON t3.i = t2.i
)
ON t2.i = t1.i
WHERE t4.i IS NULL;
i i i i
2 NULL NULL NULL
3 3 NULL NULL
4 4 4 NULL
SELECT * FROM
t1 LEFT JOIN
( ( t2 LEFT JOIN
t3
ON t3.i = t2.i
)
)
ON t2.i = t1.i
WHERE t3.i IS NULL;
i i i
2 NULL NULL
3 3 NULL
SELECT * FROM
t1 LEFT JOIN
( ( t2 LEFT JOIN
t3
ON t3.i = t2.i
)
JOIN t4
ON t4.i=t2.i
)
ON t2.i = t1.i
WHERE t3.i IS NULL;
i i i i
2 NULL NULL NULL
3 3 NULL 3
4 NULL NULL NULL
SELECT * FROM
t1 LEFT JOIN
( ( t2 LEFT JOIN
t3
ON t3.i = t2.i
)
JOIN (t4 AS t4a JOIN t4 AS t4b ON t4a.i=t4b.i)
ON t4a.i=t2.i
)
ON t2.i = t1.i
WHERE t3.i IS NULL;
i i i i i
2 NULL NULL NULL NULL
3 3 NULL 3 3
4 NULL NULL NULL NULL
SELECT * FROM
t1 LEFT JOIN
( ( t2 LEFT JOIN
t3
ON t3.i = t2.i
)
JOIN (t4 AS t4a, t4 AS t4b)
ON t4a.i=t2.i
)
ON t2.i = t1.i
WHERE t3.i IS NULL;
i i i i i
2 NULL NULL NULL NULL
3 3 NULL 3 0
3 3 NULL 3 1
3 3 NULL 3 2
3 3 NULL 3 3
4 NULL NULL NULL NULL
DROP TABLE t1,t2,t3,t4;
#
# Bug#49322(Duplicate): Server is adding extra NULL row
# on processing a WHERE clause
#
CREATE TABLE h (pk INT NOT NULL, col_int_key INT);
INSERT INTO h VALUES (1,NULL),(4,2),(5,2),(3,4),(2,8);
CREATE TABLE m (pk INT NOT NULL, col_int_key INT);
INSERT INTO m VALUES (1,2),(2,7),(3,5),(4,7),(5,5),(6,NULL),(7,NULL),(8,9);
CREATE TABLE k (pk INT NOT NULL, col_int_key INT);
INSERT INTO k VALUES (1,9),(2,2),(3,5),(4,2),(5,7),(6,0),(7,5);
SELECT TABLE1.pk FROM k TABLE1
RIGHT JOIN h TABLE2 ON TABLE1.col_int_key=TABLE2.col_int_key
RIGHT JOIN m TABLE4 ON TABLE2.col_int_key=TABLE4.col_int_key;
pk
2
2
4
4
NULL
NULL
NULL
NULL
NULL
NULL
NULL
SELECT TABLE1.pk FROM k TABLE1
RIGHT JOIN h TABLE2 ON TABLE1.col_int_key=TABLE2.col_int_key
RIGHT JOIN m TABLE4 ON TABLE2.col_int_key=TABLE4.col_int_key
WHERE TABLE1.pk IS NULL;
pk
NULL
NULL
NULL
NULL
NULL
NULL
NULL
DROP TABLE h,m,k;
#
# Bug #11765810 58813: SERVER THREAD HANGS WHEN JOIN + WHERE + GROUP BY
# IS EXECUTED TWICE FROM P
#
CREATE TABLE t1 ( a INT ) ENGINE = MYISAM;
INSERT INTO t1 VALUES (1);
PREPARE prep_stmt FROM '
SELECT 1 AS f FROM t1
LEFT JOIN t1 t2
RIGHT JOIN t1 t3
JOIN t1 t4
ON 1
ON 1
ON 1
GROUP BY f';
EXECUTE prep_stmt;
f
1
EXECUTE prep_stmt;
f
1
DROP TABLE t1;
End of 5.1 tests
#
# Bug#54235 Extra rows with join_cache_level=4,6,8 and two LEFT JOIN
#
CREATE TABLE t1 (a int);
CREATE TABLE t2 (a int);
CREATE TABLE t3 (a int);
CREATE TABLE t4 (a int);
INSERT INTO t1 VALUES (null),(null);
explain SELECT t1.a FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a)
ON 0 WHERE t1.a OR t3.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 0 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t3 ALL NULL NULL NULL NULL 0 Using where; Using join buffer (Block Nested Loop)
SELECT t1.a FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a)
ON 0 WHERE t1.a OR t3.a;
a
explain SELECT t1.a FROM t1 LEFT JOIN
(t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a)
ON 0 WHERE t1.a OR t4.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 0 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t3 ALL NULL NULL NULL NULL 0 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t4 ALL NULL NULL NULL NULL 0 Using where; Using join buffer (Block Nested Loop)
SELECT t1.a FROM t1 LEFT JOIN
(t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a)
ON 0 WHERE t1.a OR t4.a;
a
DROP TABLE t1,t2,t3,t4;
#
# Bug#56254 Assertion tab->ref.use_count fails in
# join_read_key_unlock_row() on 4-way JOIN
#
CREATE TABLE t1 (
pk INT NOT NULL,
col_int_key INT,
col_int INT,
PRIMARY KEY (pk),
KEY col_int_key (col_int_key)
);
INSERT INTO t1 VALUES (6, -448724992, NULL);
CREATE TABLE t2 (
col_int INT,
col_varchar_10 VARCHAR(10)
);
INSERT INTO t2 VALUES (6,'afasdkiyum');
CREATE TABLE t3 (
col_varchar_10 VARCHAR(10),
col_int INT
);
CREATE TABLE t4 (
pk INT NOT NULL,
PRIMARY KEY (pk)
);
INSERT INTO t4 VALUES (1);
INSERT INTO t4 VALUES (2);
SELECT t1.col_int
FROM t1
LEFT JOIN t2
LEFT JOIN t3
JOIN t4
ON t3.col_int = t4.pk
ON t2.col_varchar_10 = t3.col_varchar_10
ON t2.col_int = t1.pk
WHERE t1.col_int_key IS NULL OR t4.pk < t3.col_int;
col_int
DROP TABLE t1,t2,t3,t4;
# BUG#12567331 - INFINITE LOOP WHEN RESOLVING AN ALIASED COLUMN
# USED IN GROUP BY
CREATE TABLE t1 (pk int(11));
PREPARE prep_stmt_9846 FROM '
SELECT alias1.pk AS field1 FROM
t1 AS alias1
LEFT JOIN
(
t1 AS alias2
RIGHT JOIN
(
t1 AS alias3
JOIN t1 AS alias4
ON 1
)
ON 1
)
ON 1
GROUP BY field1';
execute prep_stmt_9846;
field1
execute prep_stmt_9846;
field1
deallocate prepare prep_stmt_9846;
drop table t1;
#
# Bug#13040136 - ASSERT IN PLAN_CHANGE_WATCHDOG::~PLAN_CHANGE_WATCHDOG()
#
CREATE TABLE t1 (
col_varchar_10 VARCHAR(10),
col_int_key INTEGER,
col_varchar_10_key VARCHAR(10),
pk INTEGER NOT NULL,
PRIMARY KEY (pk),
KEY (col_int_key),
KEY (col_varchar_10_key)
);
INSERT INTO t1 VALUES ('q',NULL,'o',1);
CREATE TABLE t2 (
pk INTEGER NOT NULL AUTO_INCREMENT,
col_varchar_10_key VARCHAR(10),
col_int_key INTEGER,
col_varchar_10 VARCHAR(10),
PRIMARY KEY (pk),
KEY (col_varchar_10_key),
KEY col_int_key (col_int_key)
);
INSERT INTO t2 VALUES
(1,'r',NULL,'would'),(2,'tell',-655032320,'t'),
(3,'d',9,'a'),(4,'gvafasdkiy',6,'ugvafasdki'),
(5,'that\'s',NULL,'she'),(6,'bwftwugvaf',7,'cbwftwugva'),
(7,'f',-700055552,'mkacbwftwu'),(8,'a',9,'be'),
(9,'d',NULL,'u'),(10,'ckiixcsxmk',NULL,'o');
SELECT DISTINCT t2.col_int_key
FROM
t1
LEFT JOIN t2
ON t1.col_varchar_10 = t2.col_varchar_10_key
WHERE t2.pk
ORDER BY t2.col_int_key;
col_int_key
DROP TABLE t1,t2;
#
# Bug#13068506 - QUERY WITH GROUP BY ON NON-AGGR COLUMN RETURNS WRONG RESULT
#
CREATE TABLE t1 (i1 int);
INSERT INTO t1 VALUES (100), (101);
CREATE TABLE t2 (i2 int, i3 int);
INSERT INTO t2 VALUES (20,1),(10,2);
CREATE TABLE t3 (i4 int(11));
INSERT INTO t3 VALUES (1),(2);
SELECT (
SELECT MAX( t2.i2 )
FROM t3 RIGHT JOIN t2 ON ( t2.i3 = 2 )
WHERE t2.i3 <> t1.i1
) AS field1
FROM t1;;
field1
20
20
SELECT (
SELECT MAX( t2.i2 )
FROM t3 RIGHT JOIN t2 ON ( t2.i3 = 2 )
WHERE t2.i3 <> t1.i1
) AS field1
FROM t1 GROUP BY field1;;
field1
20
drop table t1,t2,t3;
# Bug#11766384 - 59487: WRONG RESULT WITH STRAIGHT_JOIN AND RIGHT JOIN
CREATE TABLE t1 (
pk int(11) NOT NULL,
col_varchar_10_latin1_key varchar(10) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t1 VALUES (1,'1');
CREATE TABLE t2 (
pk int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t2 VALUES (1);
CREATE TABLE t3 (
pk int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t3 VALUES (1);
CREATE TABLE t4 (
pk int(11) NOT NULL,
col_int int(11) DEFAULT NULL,
col_int_key int(11) DEFAULT NULL,
col_varchar_10_latin1_key varchar(10) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t4 VALUES (1,1,1,'1');
CREATE TABLE t5 (
col_int int(11) DEFAULT NULL,
col_varchar_10_utf8_key varchar(10) CHARACTER SET utf8 DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t5 VALUES (1,'1');
CREATE TABLE t6 (
col_int_key int(11) DEFAULT NULL,
col_varchar_10_latin1_key varchar(10) DEFAULT NULL,
pk int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t6 VALUES (1,'1',1);
SELECT STRAIGHT_JOIN t6a.pk, t2.pk
FROM
t6 AS t6a
LEFT JOIN
(
t2
RIGHT JOIN
(
(
t1
LEFT JOIN
(
t4
JOIN
t3
ON t4.col_int
)
ON t4.col_int_key = t1.pk
)
LEFT JOIN
(
t5
JOIN
t6 AS t6b
ON t5.col_varchar_10_utf8_key = t6b.col_varchar_10_latin1_key
)
ON t1.pk = t5.col_int
)
ON t4.col_varchar_10_latin1_key = t1.col_varchar_10_latin1_key
AND t5.col_varchar_10_utf8_key = 0
)
ON t6a.pk IS TRUE
WHERE t6b.col_int_key IS TRUE
;
pk pk
1 NULL
EXPLAIN SELECT STRAIGHT_JOIN t6a.pk, t2.pk
FROM
t6 AS t6a
LEFT JOIN
(
t2
RIGHT JOIN
(
(
t1
LEFT JOIN
(
t4
JOIN
t3
ON t4.col_int
)
ON t4.col_int_key = t1.pk
)
LEFT JOIN
(
t5
JOIN
t6 AS t6b
ON t5.col_varchar_10_utf8_key = t6b.col_varchar_10_latin1_key
)
ON t1.pk = t5.col_int
)
ON t4.col_varchar_10_latin1_key = t1.col_varchar_10_latin1_key
AND t5.col_varchar_10_utf8_key = 0
)
ON t6a.pk IS TRUE
WHERE t6b.col_int_key IS TRUE
;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6a ALL NULL NULL NULL NULL 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 1 Using join buffer (Block Nested Loop)
1 SIMPLE t4 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t3 ALL NULL NULL NULL NULL 1 Using join buffer (Block Nested Loop)
1 SIMPLE t5 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t6b ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t2 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
SELECT t6a.pk, t2.pk
FROM
t6 AS t6a
LEFT JOIN
(
t2
RIGHT JOIN
(
(
t1
LEFT JOIN
(
t4
JOIN
t3
ON t4.col_int
)
ON t4.col_int_key = t1.pk
)
LEFT JOIN
(
t5
JOIN
t6 AS t6b
ON t5.col_varchar_10_utf8_key = t6b.col_varchar_10_latin1_key
)
ON t1.pk = t5.col_int
)
ON t4.col_varchar_10_latin1_key = t1.col_varchar_10_latin1_key
AND t5.col_varchar_10_utf8_key = 0
)
ON t6a.pk IS TRUE
WHERE t6b.col_int_key IS TRUE
;
pk pk
1 NULL
EXPLAIN SELECT t6a.pk, t2.pk
FROM
t6 AS t6a
LEFT JOIN
(
t2
RIGHT JOIN
(
(
t1
LEFT JOIN
(
t4
JOIN
t3
ON t4.col_int
)
ON t4.col_int_key = t1.pk
)
LEFT JOIN
(
t5
JOIN
t6 AS t6b
ON t5.col_varchar_10_utf8_key = t6b.col_varchar_10_latin1_key
)
ON t1.pk = t5.col_int
)
ON t4.col_varchar_10_latin1_key = t1.col_varchar_10_latin1_key
AND t5.col_varchar_10_utf8_key = 0
)
ON t6a.pk IS TRUE
WHERE t6b.col_int_key IS TRUE
;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6a ALL NULL NULL NULL NULL 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 1 Using join buffer (Block Nested Loop)
1 SIMPLE t4 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t3 ALL NULL NULL NULL NULL 1 Using join buffer (Block Nested Loop)
1 SIMPLE t5 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t2 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t6b ALL NULL NULL NULL NULL 1 Using where; Using join buffer (Block Nested Loop)
drop table t1,t2,t3,t4,t5,t6;
#
# Verify that the "not exists" optimization works.
#
CREATE TABLE t1(a INT);
CREATE TABLE t2(a INT NOT NULL);
INSERT INTO t1 VALUES(1),(2);
INSERT INTO t2 VALUES(1),(2);
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.a WHERE t2.a IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 NULL
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where; Not exists; Using join buffer (Block Nested Loop)
FLUSH STATUS;
SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.a WHERE t2.a IS NULL;
a a
SHOW STATUS LIKE 'HANDLER_READ%';
Variable_name Value
Handler_read_first 0
Handler_read_key 0
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_next 6
DROP TABLE t1,t2;
#
# Bug#13464334 SAME QUERY PRODUCES DIFFERENT RESULTS WHEN USED WITH AND
# WITHOUT UNION ALL
#
CREATE TABLE t1 (p1 INT PRIMARY KEY, a CHAR(1));
CREATE TABLE t2 (p2 INT PRIMARY KEY, b CHAR(1));
INSERT INTO t1 VALUES (1,'a'),(2,'b'),(3,'c');
INSERT INTO t2 VALUES (1,'h'),(2,'i'),(3,'j'),(4,'k');
CREATE VIEW v1 AS SELECT * FROM t1;
CREATE VIEW v2 AS SELECT * FROM t2;
(SELECT p1 FROM v2 LEFT JOIN v1 ON b = a WHERE p2 = 1 GROUP BY p1 ORDER BY p1)
UNION (SELECT NULL LIMIT 0);
p1
NULL
DROP VIEW v1, v2;
DROP TABLE t1, t2;
#
# Bug#13980954 Missing data on left join + null value + where..in
#
CREATE TABLE t1 (ik INT, vc varchar(1)) ENGINE=Innodb;
explain format=json SELECT straight_join t1.vc, t1.ik
FROM t1 JOIN t1 AS t2 ON t1.vc=t2.vc LEFT JOIN t1 AS t3 ON t1.vc=t3.vc;
EXPLAIN
{
"query_block": {
"select_id": 1,
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows": 1,
"filtered": 100
}
},
{
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 1,
"filtered": 100,
"using_join_buffer": "Block Nested Loop",
"attached_condition": "(`test`.`t2`.`vc` = `test`.`t1`.`vc`)"
}
},
{
"table": {
"table_name": "t3",
"access_type": "ALL",
"rows": 1,
"filtered": 100,
"using_join_buffer": "Block Nested Loop",
"attached_condition": "<if>(is_not_null_compl(t3), (`test`.`t3`.`vc` = `test`.`t1`.`vc`), true)"
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select straight_join `test`.`t1`.`vc` AS `vc`,`test`.`t1`.`ik` AS `ik` from `test`.`t1` join `test`.`t1` `t2` left join `test`.`t1` `t3` on((`test`.`t3`.`vc` = `test`.`t1`.`vc`)) where (`test`.`t2`.`vc` = `test`.`t1`.`vc`)
SELECT straight_join t1.vc, t1.ik
FROM t1 JOIN t1 AS t2 ON t1.vc=t2.vc LEFT JOIN t1 AS t3 ON t1.vc=t3.vc;
vc ik
DROP TABLE t1;
set optimizer_switch=default;