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654 lines
22 KiB
Text
654 lines
22 KiB
Text
drop table if exists t1,t2,t3,t4,t5;
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CREATE TABLE t1 (
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grp int(11) default NULL,
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a bigint(20) unsigned default NULL,
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c char(10) NOT NULL default ''
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) TYPE=MyISAM;
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INSERT INTO t1 VALUES (1,1,'a'),(2,2,'b'),(2,3,'c'),(3,4,'E'),(3,5,'C'),(3,6,'D'),(NULL,NULL,'');
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create table t2 (id int, a bigint unsigned not null, c char(10), d int, primary key (a));
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insert into t2 values (1,1,"a",1),(3,4,"A",4),(3,5,"B",5),(3,6,"C",6),(4,7,"D",7);
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select t1.*,t2.* from t1 JOIN t2 where t1.a=t2.a;
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grp a c id a c d
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1 1 a 1 1 a 1
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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select t1.*,t2.* from t1 left join t2 on (t1.a=t2.a) order by t1.grp,t1.a,t2.c;
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grp a c id a c d
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NULL NULL NULL NULL NULL NULL
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1 1 a 1 1 a 1
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2 2 b NULL NULL NULL NULL
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2 3 c NULL NULL NULL NULL
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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select t1.*,t2.* from { oj t2 left outer join t1 on (t1.a=t2.a) };
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grp a c id a c d
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1 1 a 1 1 a 1
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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NULL NULL NULL 4 7 D 7
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select t1.*,t2.* from t1 as t0,{ oj t2 left outer join t1 on (t1.a=t2.a) } WHERE t0.a=2;
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grp a c id a c d
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1 1 a 1 1 a 1
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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NULL NULL NULL 4 7 D 7
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select t1.*,t2.* from t1 left join t2 using (a);
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grp a c id a c d
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1 1 a 1 1 a 1
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2 2 b NULL NULL NULL NULL
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2 3 c NULL NULL NULL NULL
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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NULL NULL NULL NULL NULL NULL
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select t1.*,t2.* from t1 left join t2 using (a) where t1.a=t2.a;
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grp a c id a c d
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1 1 a 1 1 a 1
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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select t1.*,t2.* from t1 left join t2 using (a,c);
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grp a c id a c d
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1 1 a 1 1 a 1
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2 2 b NULL NULL NULL NULL
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2 3 c NULL NULL NULL NULL
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3 4 E NULL NULL NULL NULL
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3 5 C NULL NULL NULL NULL
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3 6 D NULL NULL NULL NULL
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NULL NULL NULL NULL NULL NULL
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select t1.*,t2.* from t1 left join t2 using (c);
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grp a c id a c d
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1 1 a 1 1 a 1
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1 1 a 3 4 A 4
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2 2 b 3 5 B 5
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2 3 c 3 6 C 6
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3 4 E NULL NULL NULL NULL
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3 5 C 3 6 C 6
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3 6 D 4 7 D 7
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NULL NULL NULL NULL NULL NULL
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select t1.*,t2.* from t1 natural left outer join t2;
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grp a c id a c d
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1 1 a 1 1 a 1
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2 2 b NULL NULL NULL NULL
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2 3 c NULL NULL NULL NULL
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3 4 E NULL NULL NULL NULL
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3 5 C NULL NULL NULL NULL
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3 6 D NULL NULL NULL NULL
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NULL NULL NULL NULL NULL NULL
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select t1.*,t2.* from t1 left join t2 on (t1.a=t2.a) where t2.id=3;
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grp a c id a c d
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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select t1.*,t2.* from t1 left join t2 on (t1.a=t2.a) where t2.id is null;
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grp a c id a c d
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2 2 b NULL NULL NULL NULL
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2 3 c NULL NULL NULL NULL
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NULL NULL NULL NULL NULL NULL
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explain select t1.*,t2.* from t1,t2 where t1.a=t2.a and isnull(t2.a)=1;
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Comment
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Impossible WHERE noticed after reading const tables
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explain select t1.*,t2.* from t1 left join t2 on t1.a=t2.a where isnull(t2.a)=1;
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table type possible_keys key key_len ref rows Extra
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t1 ALL NULL NULL NULL NULL 7
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t2 eq_ref PRIMARY PRIMARY 8 t1.a 1 where used
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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);
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grp a c id a c d a
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1 1 a 1 1 a 1 1
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2 2 b NULL NULL NULL NULL NULL
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2 3 c NULL NULL NULL NULL NULL
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3 4 E 3 4 A 4 4
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3 5 C 3 5 B 5 5
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3 6 D 3 6 C 6 6
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NULL NULL NULL NULL NULL NULL NULL
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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);
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Cross dependency found in OUTER JOIN. Examine your ON conditions
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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);
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Cross dependency found in OUTER JOIN. Examine your ON conditions
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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);
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Cross dependency found in OUTER JOIN. Examine your ON conditions
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select t1.*,t2.* from t1 inner join t2 using (a);
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grp a c id a c d
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1 1 a 1 1 a 1
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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select t1.*,t2.* from t1 inner join t2 on (t1.a=t2.a);
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grp a c id a c d
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1 1 a 1 1 a 1
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3 4 E 3 4 A 4
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3 5 C 3 5 B 5
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3 6 D 3 6 C 6
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select t1.*,t2.* from t1 natural join t2;
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grp a c id a c d
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1 1 a 1 1 a 1
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drop table t1,t2;
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CREATE TABLE t1 (
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usr_id INT unsigned NOT NULL,
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uniq_id INT unsigned NOT NULL AUTO_INCREMENT,
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start_num INT unsigned NOT NULL DEFAULT 1,
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increment INT unsigned NOT NULL DEFAULT 1,
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PRIMARY KEY (uniq_id),
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INDEX usr_uniq_idx (usr_id, uniq_id),
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INDEX uniq_usr_idx (uniq_id, usr_id)
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);
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CREATE TABLE t2 (
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id INT unsigned NOT NULL DEFAULT 0,
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usr2_id INT unsigned NOT NULL DEFAULT 0,
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max INT unsigned NOT NULL DEFAULT 0,
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c_amount INT unsigned NOT NULL DEFAULT 0,
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d_max INT unsigned NOT NULL DEFAULT 0,
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d_num INT unsigned NOT NULL DEFAULT 0,
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orig_time INT unsigned NOT NULL DEFAULT 0,
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c_time INT unsigned NOT NULL DEFAULT 0,
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active ENUM ("no","yes") NOT NULL,
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PRIMARY KEY (id,usr2_id),
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INDEX id_idx (id),
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INDEX usr2_idx (usr2_id)
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);
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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);
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SELECT t1.usr_id,t1.uniq_id,t1.increment,
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t2.usr2_id,t2.c_amount,t2.max
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FROM t1
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LEFT JOIN t2 ON t2.id = t1.uniq_id
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WHERE t1.uniq_id = 4
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ORDER BY t2.c_amount;
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usr_id uniq_id increment usr2_id c_amount max
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3 4 84676 NULL NULL NULL
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SELECT t1.usr_id,t1.uniq_id,t1.increment,
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t2.usr2_id,t2.c_amount,t2.max
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FROM t2
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RIGHT JOIN t1 ON t2.id = t1.uniq_id
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WHERE t1.uniq_id = 4
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ORDER BY t2.c_amount;
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usr_id uniq_id increment usr2_id c_amount max
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3 4 84676 NULL NULL NULL
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INSERT INTO t2 VALUES (2,3,3000,6000,0,0,746584,837484,'yes');
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INSERT INTO t2 VALUES (2,3,3000,6000,0,0,746584,837484,'yes');
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Duplicate entry '2-3' for key 1
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INSERT INTO t2 VALUES (7,3,1000,2000,0,0,746294,937484,'yes');
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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;
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usr_id uniq_id increment usr2_id c_amount max
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3 4 84676 NULL NULL NULL
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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;
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usr_id uniq_id increment usr2_id c_amount max
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3 4 84676 NULL NULL NULL
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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;
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usr_id uniq_id increment usr2_id c_amount max
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3 4 84676 NULL NULL NULL
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drop table t1,t2;
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drop table if exists t1,t2,t3,t4;
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CREATE TABLE t1 (
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cod_asig int(11) DEFAULT '0' NOT NULL,
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desc_larga_cat varchar(80) DEFAULT '' NOT NULL,
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desc_larga_cas varchar(80) DEFAULT '' NOT NULL,
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desc_corta_cat varchar(40) DEFAULT '' NOT NULL,
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desc_corta_cas varchar(40) DEFAULT '' NOT NULL,
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cred_total double(3,1) DEFAULT '0.0' NOT NULL,
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pre_requisit int(11),
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co_requisit int(11),
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preco_requisit int(11),
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PRIMARY KEY (cod_asig)
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);
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INSERT INTO t1 VALUES (10360,'asdfggfg','Introduccion a los Ordenadores I','asdfggfg','Introduccio Ordinadors I',6.0,NULL,NULL,NULL);
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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);
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INSERT INTO t1 VALUES (10362,'Laboratori d`Ordinadors','Laboratorio de Ordenadores','Laboratori d`Ordinadors','Laboratori Ordinadors',4.5,NULL,NULL,NULL);
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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);
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INSERT INTO t1 VALUES (11403,'Projecte Fi de Carrera','Proyecto Fin de Carrera','Projecte Fi de Carrera','PFC',9.0,NULL,NULL,NULL);
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INSERT INTO t1 VALUES (11404,'+lgebra lineal','Algebra lineal','+lgebra lineal','+lgebra lineal',15.0,NULL,NULL,NULL);
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INSERT INTO t1 VALUES (11405,'+lgebra lineal','Algebra lineal','+lgebra lineal','+lgebra lineal',18.0,NULL,NULL,NULL);
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INSERT INTO t1 VALUES (11406,'Calcul Infinitesimal','C<>lculo Infinitesimal','Calcul Infinitesimal','Calcul Infinitesimal',15.0,NULL,NULL,NULL);
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CREATE TABLE t2 (
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idAssignatura int(11) DEFAULT '0' NOT NULL,
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Grup int(11) DEFAULT '0' NOT NULL,
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Places smallint(6) DEFAULT '0' NOT NULL,
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PlacesOcupades int(11) DEFAULT '0',
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PRIMARY KEY (idAssignatura,Grup)
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);
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INSERT INTO t2 VALUES (10360,12,333,0);
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INSERT INTO t2 VALUES (10361,30,2,0);
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INSERT INTO t2 VALUES (10361,40,3,0);
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INSERT INTO t2 VALUES (10360,45,10,0);
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INSERT INTO t2 VALUES (10362,10,12,0);
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INSERT INTO t2 VALUES (10360,55,2,0);
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INSERT INTO t2 VALUES (10360,70,0,0);
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INSERT INTO t2 VALUES (10360,565656,0,0);
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INSERT INTO t2 VALUES (10360,32767,7,0);
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INSERT INTO t2 VALUES (10360,33,8,0);
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INSERT INTO t2 VALUES (10360,7887,85,0);
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INSERT INTO t2 VALUES (11405,88,8,0);
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INSERT INTO t2 VALUES (10360,0,55,0);
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INSERT INTO t2 VALUES (10360,99,0,0);
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INSERT INTO t2 VALUES (11411,30,10,0);
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INSERT INTO t2 VALUES (11404,0,0,0);
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INSERT INTO t2 VALUES (10362,11,111,0);
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INSERT INTO t2 VALUES (10363,33,333,0);
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INSERT INTO t2 VALUES (11412,55,0,0);
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INSERT INTO t2 VALUES (50003,66,6,0);
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INSERT INTO t2 VALUES (11403,5,0,0);
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INSERT INTO t2 VALUES (11406,11,11,0);
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INSERT INTO t2 VALUES (11410,11410,131,0);
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INSERT INTO t2 VALUES (11416,11416,32767,0);
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INSERT INTO t2 VALUES (11409,0,0,0);
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CREATE TABLE t3 (
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id int(11) DEFAULT '0' NOT NULL auto_increment,
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dni_pasaporte char(16) DEFAULT '' NOT NULL,
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idPla int(11) DEFAULT '0' NOT NULL,
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cod_asig int(11) DEFAULT '0' NOT NULL,
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any smallint(6) DEFAULT '0' NOT NULL,
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quatrimestre smallint(6) DEFAULT '0' NOT NULL,
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estat char(1) DEFAULT 'M' NOT NULL,
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PRIMARY KEY (id),
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UNIQUE dni_pasaporte (dni_pasaporte,idPla),
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UNIQUE dni_pasaporte_2 (dni_pasaporte,idPla,cod_asig,any,quatrimestre)
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);
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INSERT INTO t3 VALUES (1,'11111111',1,10362,98,1,'M');
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CREATE TABLE t4 (
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id int(11) DEFAULT '0' NOT NULL auto_increment,
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papa int(11) DEFAULT '0' NOT NULL,
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fill int(11) DEFAULT '0' NOT NULL,
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idPla int(11) DEFAULT '0' NOT NULL,
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PRIMARY KEY (id),
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KEY papa (idPla,papa),
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UNIQUE papa_2 (idPla,papa,fill)
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);
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INSERT INTO t4 VALUES (1,-1,10360,1);
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INSERT INTO t4 VALUES (2,-1,10361,1);
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INSERT INTO t4 VALUES (3,-1,10362,1);
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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;
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fill desc_larga_cat cred_total Grup Places PlacesOcupades
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10360 asdfggfg 6.0 0 55 0
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10360 asdfggfg 6.0 12 333 0
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10360 asdfggfg 6.0 33 8 0
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10360 asdfggfg 6.0 45 10 0
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10360 asdfggfg 6.0 55 2 0
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10360 asdfggfg 6.0 7887 85 0
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10360 asdfggfg 6.0 32767 7 0
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10361 Components i Circuits Electronics I 6.0 30 2 0
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10361 Components i Circuits Electronics I 6.0 40 3 0
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10362 Laboratori d`Ordinadors 4.5 10 12 0
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10362 Laboratori d`Ordinadors 4.5 11 111 0
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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 ;
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fill idPla
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10360 NULL
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10361 NULL
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10362 NULL
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INSERT INTO t3 VALUES (3,'1234',1,10360,98,1,'S');
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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 ;
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fill idPla
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10360 1
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10361 NULL
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10362 NULL
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drop table t1,t2,t3,test.t4;
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CREATE TABLE t1 (
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id smallint(5) unsigned DEFAULT '0' NOT NULL auto_increment,
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name char(60) DEFAULT '' NOT NULL,
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PRIMARY KEY (id)
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);
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INSERT INTO t1 VALUES (1,'Antonio Paz');
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INSERT INTO t1 VALUES (2,'Lilliana Angelovska');
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INSERT INTO t1 VALUES (3,'Thimble Smith');
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CREATE TABLE t2 (
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id smallint(5) unsigned DEFAULT '0' NOT NULL auto_increment,
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owner smallint(5) unsigned DEFAULT '0' NOT NULL,
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name char(60),
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PRIMARY KEY (id)
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);
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INSERT INTO t2 VALUES (1,1,'El Gato');
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INSERT INTO t2 VALUES (2,1,'Perrito');
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INSERT INTO t2 VALUES (3,3,'Happy');
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select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner);
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name name id
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Antonio Paz El Gato 1
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Antonio Paz Perrito 2
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Lilliana Angelovska NULL NULL
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Thimble Smith Happy 3
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select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.id is null;
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name name id
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Lilliana Angelovska NULL NULL
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explain select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.id is null;
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table type possible_keys key key_len ref rows Extra
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t1 ALL NULL NULL NULL NULL 3
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t2 ALL NULL NULL NULL NULL 3 where used; Not exists
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explain select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.name is null;
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table type possible_keys key key_len ref rows Extra
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t1 ALL NULL NULL NULL NULL 3
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t2 ALL NULL NULL NULL NULL 3 where used
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select count(*) from t1 left join t2 on (t1.id = t2.owner);
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count(*)
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4
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select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner);
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name name id
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Antonio Paz El Gato 1
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Antonio Paz Perrito 2
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Lilliana Angelovska NULL NULL
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Thimble Smith Happy 3
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select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.id is null;
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name name id
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Lilliana Angelovska NULL NULL
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explain select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.id is null;
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table type possible_keys key key_len ref rows Extra
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t1 ALL NULL NULL NULL NULL 3
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t2 ALL NULL NULL NULL NULL 3 where used; Not exists
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explain select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.name is null;
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table type possible_keys key key_len ref rows Extra
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t1 ALL NULL NULL NULL NULL 3
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t2 ALL NULL NULL NULL NULL 3 where used
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select count(*) from t2 right join t1 on (t1.id = t2.owner);
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count(*)
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4
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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;
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name name id id
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Antonio Paz El Gato 1 1
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Antonio Paz Perrito 2 1
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Lilliana Angelovska NULL NULL NULL
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Thimble Smith Happy 3 3
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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;
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name name id id
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Antonio Paz El Gato 1 1
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Antonio Paz Perrito 2 1
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NULL Happy 3 1
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NULL El Gato 1 2
|
||
NULL Perrito 2 2
|
||
NULL Happy 3 2
|
||
NULL El Gato 1 3
|
||
NULL Perrito 2 3
|
||
Thimble Smith Happy 3 3
|
||
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
|
||
Lilliana Angelovska NULL NULL NULL 1
|
||
Thimble Smith NULL NULL NULL 1
|
||
Antonio Paz NULL NULL NULL 2
|
||
Lilliana Angelovska NULL NULL NULL 2
|
||
Thimble Smith NULL NULL NULL 2
|
||
Antonio Paz NULL NULL NULL 3
|
||
Lilliana Angelovska NULL NULL NULL 3
|
||
Thimble Smith Happy 3 3 3
|
||
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;
|
||
id str
|
||
4 bar
|
||
3 foo
|
||
select * from t1 where str is null;
|
||
id str
|
||
1 NULL
|
||
2 NULL
|
||
drop table t1;
|
||
CREATE TABLE t1 (
|
||
t1_id bigint(21) DEFAULT '0' NOT NULL auto_increment,
|
||
PRIMARY KEY (t1_id)
|
||
);
|
||
CREATE TABLE t2 (
|
||
t2_id bigint(21) DEFAULT '0' NOT NULL auto_increment,
|
||
PRIMARY KEY (t2_id)
|
||
);
|
||
CREATE TABLE t3 (
|
||
t3_id bigint(21) DEFAULT '0' 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;
|
||
Cross dependency found in OUTER JOIN. Examine your ON conditions
|
||
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;
|
||
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;
|
||
count color color name
|
||
10 green green lime
|
||
7 green green lime
|
||
5 black black 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)
|
||
);
|
||
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;
|
||
table type possible_keys key key_len ref rows Extra
|
||
t1 ALL NULL NULL NULL NULL 2
|
||
t2 index id id 8 NULL 1 where used; Using index; Not exists
|
||
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;
|
||
table type possible_keys key key_len ref rows Extra
|
||
t2 index NULL PRIMARY 4 NULL 3 Using index
|
||
t1 eq_ref PRIMARY PRIMARY 2 const 1 where used; 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;
|