460 lines
25 KiB
Plaintext
460 lines
25 KiB
Plaintext
set optimizer_switch='semijoin=on,materialization=on,firstmatch=on,loosescan=on,index_condition_pushdown=on,mrr=on';
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SET sql_mode = 'NO_ENGINE_SUBSTITUTION';
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create table t1 (a int, b int not null,unique key (a,b),index(b)) engine=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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Warnings:
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Warning 1062 Duplicate entry '6-6' for key 'a'
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explain select * from t1 where a is null;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a a 5 const 3 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (`test`.`t1`.`a` is null)
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explain select * from t1 where a is null and b = 2;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 9 const,const 1 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = 2) and (`test`.`t1`.`a` is null))
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explain select * from t1 where a is null and b = 7;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 9 const,const 1 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = 7) and (`test`.`t1`.`a` is null))
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explain select * from t1 where a=2 and b = 2;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL const a,b a 9 const,const 1 100.00 Using index
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Warnings:
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Note 1003 /* select#1 */ select '2' AS `a`,'2' AS `b` from `test`.`t1` where true
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explain select * from t1 where a<=>b limit 2;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL index NULL a 9 NULL 12 10.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (`test`.`t1`.`a` <=> `test`.`t1`.`b`) limit 2
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a,b a 9 NULL 3 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (((`test`.`t1`.`a` is null) or ((`test`.`t1`.`a` > 0) and (`test`.`t1`.`a` < 3))) and (`test`.`t1`.`b` < 5)) limit 3
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explain format=tree select * from t1 where (a is null or a = 7) and b=7;
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EXPLAIN
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-> Filter: ((t1.b = 7) and ((t1.a is null) or (t1.a = 7))) (cost=0.46 rows=2)
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-> Index lookup on t1 using a (a=7 or NULL, b=7) (cost=0.46 rows=2)
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explain select * from t1 where (a is null or a = 7) and b=7;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref_or_null a,b a 9 const,const 2 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = 7) and ((`test`.`t1`.`a` is null) or (`test`.`t1`.`a` = 7)))
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explain select * from t1 where (a is null or a = 7) and b=7 order by a;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref_or_null a,b a 9 const,const 2 100.00 Using where; Using index; Using filesort
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = 7) and ((`test`.`t1`.`a` is null) or (`test`.`t1`.`a` = 7))) order by `test`.`t1`.`a`
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 5 const 3 40.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` > `test`.`t1`.`a`)) or ((`test`.`t1`.`b` = 7) and (`test`.`t1`.`a` is null))) limit 2
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a,b a 9 NULL 3 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (((`test`.`t1`.`b` = 9) and (`test`.`t1`.`a` is null)) or ((`test`.`t1`.`b` = 7) and (`test`.`t1`.`a` is null))) limit 3
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explain select * from t1 where a > 1 and a < 3 limit 1;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a a 5 NULL 1 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` > 1) and (`test`.`t1`.`a` < 3)) limit 1
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explain select * from t1 where a > 8 and a < 9;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a a 5 NULL 1 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` > 8) and (`test`.`t1`.`a` < 9))
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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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7 7
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NULL 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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select * from t1 where a > 1 and a < 3 limit 1;
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a b
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2 2
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select * from t1 where a > 8 and a < 9;
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a b
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create table t2 like t1;
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insert into t2 select * from t1;
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 5 const 3 10.00 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` = 2))
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explain select * from t1 where a is null and b = 2 and c=0;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 5 const 3 8.33 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`c` = 0) and (`test`.`t1`.`a` is null) and (`test`.`t1`.`b` = 2))
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explain select * from t1 where a is null and b = 7 and c=0;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 5 const 3 8.33 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`c` = 0) and (`test`.`t1`.`a` is null) and (`test`.`t1`.`b` = 7))
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explain select * from t1 where a=2 and b = 2;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 5 const 1 10.00 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`a` = 2) and (`test`.`t1`.`b` = 2))
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explain select * from t1 where a<=>b limit 2;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 12 10.00 Using where
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (`test`.`t1`.`a` <=> `test`.`t1`.`b`) limit 2
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a,b a 5 NULL 5 8.33 Using where
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Warnings:
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`c` = 0) and ((`test`.`t1`.`a` is null) or ((`test`.`t1`.`a` > 0) and (`test`.`t1`.`a` < 3))) and (`test`.`t1`.`b` < 5)) limit 3
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref_or_null a,b a 5 const 4 8.33 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`c` = 0) and ((`test`.`t1`.`a` is null) or (`test`.`t1`.`a` = 7)) and (`test`.`t1`.`b` = 7))
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 5 const 3 40.00 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` > `test`.`t1`.`a`)) or ((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` = 7))) limit 2
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref a,b a 5 const 3 19.00 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` = 9)) or ((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` = 7))) limit 3
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explain select * from t1 where a > 1 and a < 3 limit 1;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a a 5 NULL 1 100.00 Using where
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`a` > 1) and (`test`.`t1`.`a` < 3)) limit 1
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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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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a,b a 5 NULL 4 100.00 Using where
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Warnings:
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Warning 1739 Cannot use ref access on index 'b' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'a' due to type or collation conversion on field 'b'
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Warning 1739 Cannot use range access on index 'b' due to type or collation conversion on field 'b'
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` = 7)) or ((`test`.`t1`.`a` > 1) and (`test`.`t1`.`a` < 3))) limit 1
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explain select * from t1 where a > 8 and a < 9;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range a a 5 NULL 1 100.00 Using where
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`a` > 8) and (`test`.`t1`.`a` < 9))
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explain select * from t1 where b like "6%";
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL range b b 12 NULL 1 100.00 Using where
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (`test`.`t1`.`b` like '6%')
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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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7 7 0
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NULL 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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rename table t2 to t1;
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alter table t1 modify b int null;
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insert into t1 values (7,null), (8,null), (8,7);
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explain select * from t1 where a = 7 and (b=7 or b is null);
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref_or_null a,b a 10 const,const 2 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 7) and ((`test`.`t1`.`b` = 7) or (`test`.`t1`.`b` is null)))
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select * from t1 where a = 7 and (b=7 or b is null);
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a b
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7 7
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7 NULL
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explain select * from t1 where (a = 7 or a is null) and (b=7 or b is null);
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref_or_null a,b a 5 const 4 33.33 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (((`test`.`t1`.`a` = 7) or (`test`.`t1`.`a` is null)) and ((`test`.`t1`.`b` = 7) or (`test`.`t1`.`b` is null)))
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select * from t1 where (a = 7 or a is null) and (b=7 or b is null);
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a b
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7 NULL
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7 7
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NULL 7
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explain select * from t1 where (a = 7 or a is null) and (a = 7 or a is null);
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 NULL ref_or_null a a 5 const 5 100.00 Using where; Using index
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (((`test`.`t1`.`a` = 7) or (`test`.`t1`.`a` is null)) and ((`test`.`t1`.`a` = 7) or (`test`.`t1`.`a` is null)))
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select * from t1 where (a = 7 or a is null) and (a = 7 or a is null);
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a b
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7 NULL
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7 7
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NULL 7
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NULL 9
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NULL 9
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create table t2 (a int);
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insert into t2 values (7),(8);
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explain select * from t2 straight_join t1 where t1.a=t2.a and b is null;
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id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 100.00 Using where
|
|
1 SIMPLE t1 NULL ref a,b a 10 test.t2.a,const 2 100.00 Using where; Using index
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t2` straight_join `test`.`t1` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` is null))
|
|
drop index b on t1;
|
|
explain select * from t2,t1 where t1.a=t2.a and b is null;
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 100.00 Using where
|
|
1 SIMPLE t1 NULL ref a a 10 test.t2.a,const 2 100.00 Using where; Using index
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t2` join `test`.`t1` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` is null))
|
|
select * from t2,t1 where t1.a=t2.a and b is null;
|
|
a a b
|
|
7 7 NULL
|
|
8 8 NULL
|
|
explain select * from t2,t1 where t1.a=t2.a and (b= 7 or b is null);
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 100.00 Using where
|
|
1 SIMPLE t1 NULL ref_or_null a a 10 test.t2.a,const 4 100.00 Using where; Using index
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t2` join `test`.`t1` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and ((`test`.`t1`.`b` = 7) or (`test`.`t1`.`b` is null)))
|
|
select * from t2,t1 where t1.a=t2.a and (b= 7 or b is null);
|
|
a a b
|
|
7 7 7
|
|
7 7 NULL
|
|
8 8 7
|
|
8 8 NULL
|
|
explain select * from t2,t1 where (t1.a=t2.a or t1.a is null) and b= 7;
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 100.00 NULL
|
|
1 SIMPLE t1 NULL ref_or_null a a 10 test.t2.a,const 4 100.00 Using where; Using index
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t2` join `test`.`t1` where ((`test`.`t1`.`b` = 7) and ((`test`.`t1`.`a` = `test`.`t2`.`a`) or (`test`.`t1`.`a` is null)))
|
|
select * from t2,t1 where (t1.a=t2.a or t1.a is null) and b= 7;
|
|
a a b
|
|
7 7 7
|
|
7 NULL 7
|
|
8 8 7
|
|
8 NULL 7
|
|
explain select * from t2,t1 where (t1.a=t2.a or t1.a is null) and (b= 7 or b is null);
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 100.00 NULL
|
|
1 SIMPLE t1 NULL ref_or_null a a 5 test.t2.a 4 19.00 Using where; Using index
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t2` join `test`.`t1` where (((`test`.`t1`.`a` = `test`.`t2`.`a`) or (`test`.`t1`.`a` is null)) and ((`test`.`t1`.`b` = 7) or (`test`.`t1`.`b` is null)))
|
|
select * from t2,t1 where (t1.a=t2.a or t1.a is null) and (b= 7 or b is null);
|
|
a a b
|
|
7 7 NULL
|
|
7 7 7
|
|
7 NULL 7
|
|
8 8 NULL
|
|
8 8 7
|
|
8 NULL 7
|
|
insert into t2 values (null),(6);
|
|
delete from t1 where a=8;
|
|
explain select * from t2,t1 where t1.a=t2.a or t1.a is null;
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL
|
|
1 SIMPLE t1 NULL ref_or_null a a 5 test.t2.a 4 100.00 Using where; Using index
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t2` join `test`.`t1` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) or (`test`.`t1`.`a` is null))
|
|
explain select * from t2,t1 where t1.a<=>t2.a or (t1.a is null and t1.b <> 9);
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 4 100.00 NULL
|
|
1 SIMPLE t1 NULL ref_or_null a a 5 test.t2.a 4 100.00 Using where; Using index
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t2` join `test`.`t1` where ((`test`.`t1`.`a` <=> `test`.`t2`.`a`) or ((`test`.`t1`.`a` is null) and (`test`.`t1`.`b` <> 9)))
|
|
select * from t2,t1 where t1.a<=>t2.a or (t1.a is null and t1.b <> 9);
|
|
a a b
|
|
7 7 NULL
|
|
7 7 7
|
|
7 NULL 7
|
|
8 NULL 7
|
|
NULL NULL 7
|
|
NULL NULL 9
|
|
NULL NULL 9
|
|
6 6 6
|
|
6 NULL 7
|
|
drop table t1,t2;
|
|
CREATE TABLE t1 (
|
|
id int(10) unsigned NOT NULL auto_increment,
|
|
uniq_id int(10) unsigned default NULL,
|
|
PRIMARY KEY (id),
|
|
UNIQUE KEY idx1 (uniq_id)
|
|
) ENGINE=MyISAM;
|
|
Warnings:
|
|
Warning 1681 Integer display width is deprecated and will be removed in a future release.
|
|
Warning 1681 Integer display width is deprecated and will be removed in a future release.
|
|
CREATE TABLE t2 (
|
|
id int(10) unsigned NOT NULL auto_increment,
|
|
uniq_id int(10) unsigned default NULL,
|
|
PRIMARY KEY (id)
|
|
) ENGINE=MyISAM;
|
|
Warnings:
|
|
Warning 1681 Integer display width is deprecated and will be removed in a future release.
|
|
Warning 1681 Integer display width is deprecated and will be removed in a future release.
|
|
INSERT INTO t1 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
|
|
INSERT INTO t2 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
|
|
explain select id from t1 where uniq_id is null;
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t1 NULL ref idx1 idx1 5 const 5 100.00 Using index condition
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t1`.`id` AS `id` from `test`.`t1` where (`test`.`t1`.`uniq_id` is null)
|
|
explain select id from t1 where uniq_id =1;
|
|
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t1 NULL const idx1 idx1 5 const 1 100.00 NULL
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select '3' AS `id` from `test`.`t1` where true
|
|
UPDATE t1 SET id=id+100 where uniq_id is null;
|
|
UPDATE t2 SET id=id+100 where uniq_id is null;
|
|
select id from t1 where uniq_id is null;
|
|
id
|
|
101
|
|
102
|
|
105
|
|
106
|
|
109
|
|
110
|
|
select id from t2 where uniq_id is null;
|
|
id
|
|
101
|
|
102
|
|
105
|
|
106
|
|
109
|
|
110
|
|
DELETE FROM t1 WHERE uniq_id IS NULL;
|
|
DELETE FROM t2 WHERE uniq_id IS NULL;
|
|
SELECT * FROM t1 ORDER BY uniq_id, id;
|
|
id uniq_id
|
|
3 1
|
|
4 2
|
|
7 3
|
|
8 4
|
|
SELECT * FROM t2 ORDER BY uniq_id, id;
|
|
id uniq_id
|
|
3 1
|
|
4 2
|
|
7 3
|
|
8 4
|
|
DROP table t1,t2;
|
|
CREATE TABLE `t1` (
|
|
`order_id` char(32) NOT NULL default '',
|
|
`product_id` char(32) NOT NULL default '',
|
|
`product_type` int(11) NOT NULL default '0',
|
|
PRIMARY KEY (`order_id`,`product_id`,`product_type`)
|
|
) ENGINE=MyISAM;
|
|
Warnings:
|
|
Warning 1681 Integer display width is deprecated and will be removed in a future release.
|
|
CREATE TABLE `t2` (
|
|
`order_id` char(32) NOT NULL default '',
|
|
`product_id` char(32) NOT NULL default '',
|
|
`product_type` int(11) NOT NULL default '0',
|
|
PRIMARY KEY (`order_id`,`product_id`,`product_type`)
|
|
) ENGINE=MyISAM;
|
|
Warnings:
|
|
Warning 1681 Integer display width is deprecated and will be removed in a future release.
|
|
INSERT INTO t1 (order_id, product_id, product_type) VALUES
|
|
('3d7ce39b5d4b3e3d22aaafe9b633de51',1206029, 3),
|
|
('3d7ce39b5d4b3e3d22aaafe9b633de51',5880836, 3),
|
|
('9d9aad7764b5b2c53004348ef8d34500',2315652, 3);
|
|
INSERT INTO t2 (order_id, product_id, product_type) VALUES
|
|
('9d9aad7764b5b2c53004348ef8d34500',2315652, 3);
|
|
select t1.* from t1
|
|
left join t2 using(order_id, product_id, product_type)
|
|
where t2.order_id=NULL;
|
|
order_id product_id product_type
|
|
select t1.* from t1
|
|
left join t2 using(order_id, product_id, product_type)
|
|
where t2.order_id is NULL;
|
|
order_id product_id product_type
|
|
3d7ce39b5d4b3e3d22aaafe9b633de51 1206029 3
|
|
3d7ce39b5d4b3e3d22aaafe9b633de51 5880836 3
|
|
drop table t1,t2;
|
|
SET sql_mode = default;
|
|
create table t1 (a int, b int not null,unique key (b,a),index(b));
|
|
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);
|
|
Warnings:
|
|
Warning 1062 Duplicate entry '6-6' for key 'b'
|
|
explain format=tree select * from t1 where (a is null or a = 7) and b=7;
|
|
EXPLAIN
|
|
-> Filter: ((t1.b = 7) and ((t1.a is null) or (t1.a = 7))) (cost=0.46 rows=2)
|
|
-> Index lookup on t1 using b (b=7, a=7 or NULL) (cost=0.46 rows=2)
|
|
|
|
drop table t1;
|
|
set optimizer_switch=default;
|