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drop table if exists t1;
CREATE TABLE t1 (
a char(5) NOT NULL,
b char(4) NOT NULL,
KEY (a),
KEY (b)
);
INSERT INTO t1 VALUES ('A','B'),('b','A'),('C','c'),('D','E'),('a','a');
select * from t1,t1 as t2;
a b a b
A B A B
b A A B
C c A B
D E A B
a a A B
A B b A
b A b A
C c b A
D E b A
a a b A
A B C c
b A C c
C c C c
D E C c
a a C c
A B D E
b A D E
C c D E
D E D E
a a D E
A B a a
b A a a
C c a a
D E a a
a a a a
analyze table t1;
Table Op Msg_type Msg_text
test.t1 analyze status OK
explain select t1.*,t2.* from t1,t1 as t2 where t1.A=t2.B;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL ALL a NULL NULL NULL 5 100.00 NULL
1 SIMPLE t2 NULL ALL b NULL NULL NULL 5 20.00 Using where; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` join `test`.`t1` `t2` where (`test`.`t1`.`a` = `test`.`t2`.`b`)
select t1.*,t2.* from t1,t1 as t2 where t1.A=t2.B order by binary t1.a,t2.a;
a b a b
A B a a
A B b A
C c C c
a a a a
a a b A
b A A B
select * from t1 where a='a';
a b
A B
a a
drop table t1;