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MWL#17: Table elimination

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- More test coverage
- Remove unused code
This commit is contained in:
Sergey Petrunya
2009-08-25 13:38:22 +03:00
parent 9400700b99
commit de41681afa
3 changed files with 14 additions and 12 deletions
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11
mysql-test/r/table_elim.result
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@ -314,8 +314,8 @@ create table t1 (a int, b int, c int, d int);
insert into t1 values (0,0,0,0),(1,1,1,1),(2,2,2,2),(3,3,3,3);
create table t2 (pk int primary key, b int)
as select a as pk, a as b from t1 where a in (1,2);
create table t3 (pk int primary key, b int)
as select a as pk, a as b from t1 where a in (1,3);
create table t3 (pk1 int, pk2 int, b int, unique(pk1,pk2));
insert into t3 select a as pk1, a as pk2, a as b from t1 where a in (1,3);
explain select t1.a from t1 left join t2 on t2.pk=t1.a and t2.b<t1.b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
@ -344,4 +344,11 @@ id select_type table type possible_keys key key_len ref rows Extra
explain select t1.a from t1 left join t2 on t2.pk in (t1.a);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
explain select t1.a from t1 left join t2 on TRUE;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
1 SIMPLE t2 index NULL PRIMARY 4 NULL 2 Using index
explain select t1.a from t1 left join t3 on t3.pk1=t1.a and t3.pk2 IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
drop table t1,t2,t3;