53 lines
829 B
Plaintext
53 lines
829 B
Plaintext
|
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
|
||
|
|
explain select t1.*,t2.* from t1,t1 as t2 where t1.A=t2.B;
|
||
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
||
|
|
1 SIMPLE t1 ALL a NULL NULL NULL 5
|
||
|
|
1 SIMPLE t2 ALL b NULL NULL NULL 5 Using where; Using join buffer
|
||
|
|
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;
|