mirror of
https://github.com/MariaDB/server.git
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f6a43bd567
Added optimzation for clustered index Fixed bug in UPDATE ... ORDER BY Fixed handling of UPDATE ... LIMIT
264 lines
8.1 KiB
Plaintext
264 lines
8.1 KiB
Plaintext
drop table if exists t1;
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create table t1 (a int, b int not null,unique key (a,b),index(b)) type=myisam;
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insert ignore into t1 values (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(null,7),(9,9),(8,8),(7,7),(null,9),(null,9),(6,6);
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explain select * from t1 where a is null;
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table type possible_keys key key_len ref rows Extra
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t1 ref a a 5 const 3 Using where; Using index
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explain select * from t1 where a is null and b = 2;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 9 const,const 1 Using where; Using index
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explain select * from t1 where a is null and b = 7;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 9 const,const 1 Using where; Using index
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explain select * from t1 where a=2 and b = 2;
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table type possible_keys key key_len ref rows Extra
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t1 const a,b a 9 const,const 1
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explain select * from t1 where a<=>b limit 2;
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table type possible_keys key key_len ref rows Extra
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t1 index NULL a 9 NULL 12 Using where; Using index
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explain select * from t1 where (a is null or a > 0 and a < 3) and b < 5 limit 3;
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table type possible_keys key key_len ref rows Extra
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t1 range a,b a 9 NULL 3 Using where; Using index
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explain select * from t1 where (a is null or a = 7) and b=7;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b b 4 const 2 Using where
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explain select * from t1 where (a is null and b>a) or a is null and b=7 limit 2;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 5 const 3 Using where; Using index
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explain select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
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table type possible_keys key key_len ref rows Extra
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t1 range a,b a 9 NULL 2 Using where; Using index
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explain select * from t1 where a > 1 and a < 3 limit 1;
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table type possible_keys key key_len ref rows Extra
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t1 range a a 5 NULL 1 Using where; Using index
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explain select * from t1 where a > 8 and a < 9;
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table type possible_keys key key_len ref rows Extra
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t1 range a a 5 NULL 1 Using where; Using index
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select * from t1 where a is null;
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a b
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NULL 7
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NULL 9
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NULL 9
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select * from t1 where a is null and b = 7;
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a b
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NULL 7
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select * from t1 where a<=>b limit 2;
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a b
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1 1
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2 2
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select * from t1 where (a is null or a > 0 and a < 3) and b < 5 limit 3;
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a b
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1 1
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2 2
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select * from t1 where (a is null or a > 0 and a < 3) and b > 7 limit 3;
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a b
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NULL 9
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NULL 9
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select * from t1 where (a is null or a = 7) and b=7;
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a b
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NULL 7
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7 7
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select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
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a b
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NULL 7
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NULL 9
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NULL 9
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alter table t1 modify b blob not null, add c int not null, drop key a, add unique key (a,b(20),c), drop key b, add key (b(10));
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explain select * from t1 where a is null and b = 2;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 5 const 3 Using where
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explain select * from t1 where a is null and b = 2 and c=0;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 5 const 3 Using where
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explain select * from t1 where a is null and b = 7 and c=0;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 5 const 3 Using where
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explain select * from t1 where a=2 and b = 2;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 5 const 1 Using where
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explain select * from t1 where a<=>b limit 2;
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table type possible_keys key key_len ref rows Extra
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t1 ALL NULL NULL NULL NULL 12 Using where
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explain select * from t1 where (a is null or a > 0 and a < 3) and b < 5 and c=0 limit 3;
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table type possible_keys key key_len ref rows Extra
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t1 range a,b a 5 NULL 5 Using where
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explain select * from t1 where (a is null or a = 7) and b=7 and c=0;
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table type possible_keys key key_len ref rows Extra
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t1 ALL a,b NULL NULL NULL 12 Using where
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explain select * from t1 where (a is null and b>a) or a is null and b=7 limit 2;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 5 const 3 Using where
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explain select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
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table type possible_keys key key_len ref rows Extra
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t1 ref a,b a 5 const 3 Using where
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explain select * from t1 where a > 1 and a < 3 limit 1;
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table type possible_keys key key_len ref rows Extra
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t1 range a a 5 NULL 1 Using where
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explain select * from t1 where a is null and b=7 or a > 1 and a < 3 limit 1;
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table type possible_keys key key_len ref rows Extra
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t1 range a,b a 5 NULL 4 Using where
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explain select * from t1 where a > 8 and a < 9;
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table type possible_keys key key_len ref rows Extra
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t1 range a a 5 NULL 1 Using where
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explain select * from t1 where b like "6%";
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table type possible_keys key key_len ref rows Extra
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t1 range b b 12 NULL 1 Using where
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select * from t1 where a is null;
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a b c
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NULL 7 0
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NULL 9 0
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NULL 9 0
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select * from t1 where a is null and b = 7 and c=0;
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a b c
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NULL 7 0
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select * from t1 where a<=>b limit 2;
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a b c
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1 1 0
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2 2 0
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select * from t1 where (a is null or a > 0 and a < 3) and b < 5 limit 3;
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a b c
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1 1 0
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2 2 0
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select * from t1 where (a is null or a > 0 and a < 3) and b > 7 limit 3;
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a b c
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NULL 9 0
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NULL 9 0
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select * from t1 where (a is null or a = 7) and b=7 and c=0;
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a b c
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NULL 7 0
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7 7 0
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select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
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a b c
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NULL 7 0
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NULL 9 0
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NULL 9 0
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select * from t1 where b like "6%";
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a b c
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6 6 0
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drop table t1;
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DROP TABLE IF EXISTS t1,t2;
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CREATE TABLE t1 (
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id int(10) unsigned NOT NULL auto_increment,
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uniq_id int(10) unsigned default NULL,
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PRIMARY KEY (id),
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UNIQUE KEY idx1 (uniq_id)
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) TYPE=MyISAM;
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CREATE TABLE t2 (
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id int(10) unsigned NOT NULL auto_increment,
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uniq_id int(10) unsigned default NULL,
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PRIMARY KEY (id)
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) TYPE=MyISAM;
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INSERT INTO t1 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
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INSERT INTO t2 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
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explain select id from t1 where uniq_id is null;
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table type possible_keys key key_len ref rows Extra
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t1 ref idx1 idx1 5 const 1 Using where
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explain select id from t1 where uniq_id =1;
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table type possible_keys key key_len ref rows Extra
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t1 const idx1 idx1 5 const 1
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UPDATE t1 SET id=id+100 where uniq_id is null;
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UPDATE t2 SET id=id+100 where uniq_id is null;
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select id from t1 where uniq_id is null;
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id
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101
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102
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105
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106
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109
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110
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select id from t2 where uniq_id is null;
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id
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101
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102
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105
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106
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109
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110
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DELETE FROM t1 WHERE uniq_id IS NULL;
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DELETE FROM t2 WHERE uniq_id IS NULL;
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SELECT * FROM t1 ORDER BY uniq_id, id;
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id uniq_id
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3 1
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4 2
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7 3
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8 4
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SELECT * FROM t2 ORDER BY uniq_id, id;
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id uniq_id
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3 1
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4 2
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7 3
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8 4
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DROP table t1,t2;
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CREATE TABLE `t1` (
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`order_id` char(32) NOT NULL default '',
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`product_id` char(32) NOT NULL default '',
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`product_type` int(11) NOT NULL default '0',
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PRIMARY KEY (`order_id`,`product_id`,`product_type`)
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) TYPE=MyISAM;
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CREATE TABLE `t2` (
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`order_id` char(32) NOT NULL default '',
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`product_id` char(32) NOT NULL default '',
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`product_type` int(11) NOT NULL default '0',
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PRIMARY KEY (`order_id`,`product_id`,`product_type`)
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) TYPE=MyISAM;
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INSERT INTO t1 (order_id, product_id, product_type) VALUES
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('3d7ce39b5d4b3e3d22aaafe9b633de51',1206029, 3),
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('3d7ce39b5d4b3e3d22aaafe9b633de51',5880836, 3),
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('9d9aad7764b5b2c53004348ef8d34500',2315652, 3);
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INSERT INTO t2 (order_id, product_id, product_type) VALUES
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('9d9aad7764b5b2c53004348ef8d34500',2315652, 3);
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select t1.* from t1
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left join t2 using(order_id, product_id, product_type)
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where t2.order_id=NULL;
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order_id product_id product_type
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select t1.* from t1
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left join t2 using(order_id, product_id, product_type)
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where t2.order_id is NULL;
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order_id product_id product_type
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3d7ce39b5d4b3e3d22aaafe9b633de51 1206029 3
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3d7ce39b5d4b3e3d22aaafe9b633de51 5880836 3
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drop table t1,t2;
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create table t1 (id int);
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insert into t1 values (null), (0);
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create table t2 (id int);
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insert into t2 values (null);
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select * from t1, t2 where t1.id = t2.id;
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id id
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alter table t1 add key id (id);
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select * from t1, t2 where t1.id = t2.id;
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id id
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drop table t1,t2;
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create table t1 (
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id integer,
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id2 integer not null,
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index (id),
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index (id2)
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);
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insert into t1 values(null,null),(1,1);
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select * from t1;
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id id2
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NULL 0
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1 1
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select * from t1 where id <=> null;
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id id2
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NULL 0
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select * from t1 where id <=> null or id > 0;
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id id2
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NULL 0
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1 1
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select * from t1 where id is null or id > 0;
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id id2
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NULL 0
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1 1
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select * from t1 where id2 <=> null or id2 > 0;
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id id2
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1 1
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select * from t1 where id2 is null or id2 > 0;
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id id2
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1 1
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delete from t1 where id <=> NULL;
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select * from t1;
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id id2
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1 1
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drop table t1;
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