mirror of
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715dc5f99d
of the 5.3 code line after a merge with 5.2 on 2010-10-28 in order not to allow the cost to access a joined table to be equal to 0 ever. Expanded data sets for many test cases to get the same execution plans as before.
61 lines
1.1 KiB
Plaintext
61 lines
1.1 KiB
Plaintext
drop table if exists t1;
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CREATE TABLE t1 (
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a char(5) NOT NULL,
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b char(4) NOT NULL,
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KEY (a),
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KEY (b)
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);
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INSERT INTO t1 VALUES ('A','B'),('b','A'),('C','c'),('D','E'),('a','a');
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INSERT INTO t1 VALUES
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('AA','BB'),('bb','AA'),('CC','cc'),('DD','EE'),('aa','aa');
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INSERT INTO t1 VALUES
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('AAA','BBB'),('bbb','AAA'),('CCC','ccc'),('DDD','EEE'),('aaa','aaa');
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select * from t1,t1 as t2
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where length(t1.A)=1 and length(t2.B)=1 ;
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a b a b
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A B A B
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b A A B
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C c A B
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D E A B
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a a A B
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A B b A
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b A b A
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C c b A
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D E b A
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a a b A
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A B C c
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b A C c
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C c C c
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D E C c
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a a C c
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A B D E
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b A D E
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C c D E
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D E D E
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a a D E
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A B a a
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b A a a
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C c a a
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D E a a
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a a a a
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explain select t1.*,t2.* from t1,t1 as t2
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where t1.A=t2.B and length(t1.A)=1 and length(t2.B)=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL a NULL NULL NULL 15 Using where
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1 SIMPLE t2 ref b b 4 test.t1.a 1 Using where
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select t1.*,t2.* from t1,t1 as t2
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where t1.A=t2.B and length(t1.A)=1 and length(t2.B)=1
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order by binary t1.a,t2.a;
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a b a b
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A B a a
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A B b A
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C c C c
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a a a a
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a a b A
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b A A B
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select * from t1 where a='a';
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a b
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A B
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a a
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drop table t1;
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