2004-08-27 16:37:13 +03:00
drop table if exists t1;
create table t1 (
a1 char(64), a2 char(64), b char(16), c char(16) not null, d char(16), dummy char(64) default ' '
);
insert into t1 (a1, a2, b, c, d) values
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4'),
('d','a','a','a411','xy1'),('d','a','a','b411','xy2'),('d','a','a','c411','xy3'),('d','a','a','d411','xy4'),
('d','a','b','e412','xy1'),('d','a','b','f412','xy2'),('d','a','b','g412','xy3'),('d','a','b','h412','xy4'),
('d','b','a','i421','xy1'),('d','b','a','j421','xy2'),('d','b','a','k421','xy3'),('d','b','a','l421','xy4'),
('d','b','b','m422','xy1'),('d','b','b','n422','xy2'),('d','b','b','o422','xy3'),('d','b','b','p422','xy4'),
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4'),
('d','a','a','a411','xy1'),('d','a','a','b411','xy2'),('d','a','a','c411','xy3'),('d','a','a','d411','xy4'),
('d','a','b','e412','xy1'),('d','a','b','f412','xy2'),('d','a','b','g412','xy3'),('d','a','b','h412','xy4'),
('d','b','a','i421','xy1'),('d','b','a','j421','xy2'),('d','b','a','k421','xy3'),('d','b','a','l421','xy4'),
('d','b','b','m422','xy1'),('d','b','b','n422','xy2'),('d','b','b','o422','xy3'),('d','b','b','p422','xy4');
create index idx_t1_0 on t1 (a1);
create index idx_t1_1 on t1 (a1,a2,b,c);
create index idx_t1_2 on t1 (a1,a2,b);
analyze table t1;
Table Op Msg_type Msg_text
test.t1 analyze status Table is already up to date
drop table if exists t2;
create table t2 (
a1 char(64), a2 char(64) not null, b char(16), c char(16), d char(16), dummy char(64) default ' '
);
insert into t2 select * from t1;
insert into t2 (a1, a2, b, c, d) values
('a','a',NULL,'a777','xyz'),('a','a',NULL,'a888','xyz'),('a','a',NULL,'a999','xyz'),
('a','a','a',NULL,'xyz'),
('a','a','b',NULL,'xyz'),
('a','b','a',NULL,'xyz'),
('c','a',NULL,'c777','xyz'),('c','a',NULL,'c888','xyz'),('c','a',NULL,'c999','xyz'),
('d','b','b',NULL,'xyz'),
('e','a','a',NULL,'xyz'),('e','a','a',NULL,'xyz'),('e','a','a',NULL,'xyz'),('e','a','a',NULL,'xyz'),
('e','a','b',NULL,'xyz'),('e','a','b',NULL,'xyz'),('e','a','b',NULL,'xyz'),('e','a','b',NULL,'xyz'),
('a','a',NULL,'a777','xyz'),('a','a',NULL,'a888','xyz'),('a','a',NULL,'a999','xyz'),
('a','a','a',NULL,'xyz'),
('a','a','b',NULL,'xyz'),
('a','b','a',NULL,'xyz'),
('c','a',NULL,'c777','xyz'),('c','a',NULL,'c888','xyz'),('c','a',NULL,'c999','xyz'),
('d','b','b',NULL,'xyz'),
('e','a','a',NULL,'xyz'),('e','a','a',NULL,'xyz'),('e','a','a',NULL,'xyz'),('e','a','a',NULL,'xyz'),
('e','a','b',NULL,'xyz'),('e','a','b',NULL,'xyz'),('e','a','b',NULL,'xyz'),('e','a','b',NULL,'xyz');
create index idx_t2_0 on t2 (a1);
create index idx_t2_1 on t2 (a1,a2,b,c);
create index idx_t2_2 on t2 (a1,a2,b);
analyze table t2;
Table Op Msg_type Msg_text
test.t2 analyze status Table is already up to date
drop table if exists t3;
create table t3 (
a1 char(1), a2 char(1), b char(1), c char(4) not null, d char(3), dummy char(1) default ' '
);
insert into t3 (a1, a2, b, c, d) values
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4');
insert into t3 (a1, a2, b, c, d) values
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4');
insert into t3 (a1, a2, b, c, d) values
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4');
insert into t3 (a1, a2, b, c, d) values
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4');
create index idx_t3_0 on t3 (a1);
create index idx_t3_1 on t3 (a1,a2,b,c);
create index idx_t3_2 on t3 (a1,a2,b);
analyze table t3;
Table Op Msg_type Msg_text
test.t3 analyze status Table is already up to date
explain select a1, min(a2) from t1 group by a1;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-30 20:54:37 +04:00
1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1, max(a2) from t1 group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 65 NULL 5 Using index for group-by
explain select a1, min(a2), max(a2) from t1 group by a1;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-30 20:54:37 +04:00
1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1, a2, b, min(c), max(c) from t1 group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using index for group-by
explain select a1,a2,b,max(c),min(c) from t1 group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using index for group-by
explain select a1,a2,b,max(c),min(c) from t2 group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-19 05:54:31 +03:00
1 SIMPLE t2 range NULL idx_t2_1 # NULL # Using index for group-by
2004-08-27 16:37:13 +03:00
explain select min(a2), a1, max(a2), min(a2), a1 from t1 group by a1;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-30 20:54:37 +04:00
1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1, b, min(c), a1, max(c), b, a2, max(c), max(c) from t1 group by a1, a2, b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using index for group-by
explain select min(a2) from t1 group by a1;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-30 20:54:37 +04:00
1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a2, min(c), max(c) from t1 group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using index for group-by
select a1, min(a2) from t1 group by a1;
a1 min(a2)
a a
b a
c a
d a
select a1, max(a2) from t1 group by a1;
a1 max(a2)
a b
b b
c b
d b
select a1, min(a2), max(a2) from t1 group by a1;
a1 min(a2) max(a2)
a a b
b a b
c a b
d a b
select a1, a2, b, min(c), max(c) from t1 group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b,max(c),min(c) from t1 group by a1,a2,b;
a1 a2 b max(c) min(c)
a a a d111 a111
a a b h112 e112
a b a l121 i121
a b b p122 m122
b a a d211 a211
b a b h212 e212
b b a l221 i221
b b b p222 m222
c a a d311 a311
c a b h312 e312
c b a l321 i321
c b b p322 m322
d a a d411 a411
d a b h412 e412
d b a l421 i421
d b b p422 m422
select a1,a2,b,max(c),min(c) from t2 group by a1,a2,b;
a1 a2 b max(c) min(c)
a a NULL a999 a777
a a a d111 a111
a a b h112 e112
a b a l121 i121
a b b p122 m122
b a a d211 a211
b a b h212 e212
b b a l221 i221
b b b p222 m222
c a NULL c999 c777
c a a d311 a311
c a b h312 e312
c b a l321 i321
c b b p322 m322
d a a d411 a411
d a b h412 e412
d b a l421 i421
d b b p422 m422
e a a NULL NULL
e a b NULL NULL
select min(a2), a1, max(a2), min(a2), a1 from t1 group by a1;
min(a2) a1 max(a2) min(a2) a1
a a b a a
a b b a b
a c b a c
a d b a d
select a1, b, min(c), a1, max(c), b, a2, max(c), max(c) from t1 group by a1, a2, b;
a1 b min(c) a1 max(c) b a2 max(c) max(c)
a a a111 a d111 a a d111 d111
a b e112 a h112 b a h112 h112
a a i121 a l121 a b l121 l121
a b m122 a p122 b b p122 p122
b a a211 b d211 a a d211 d211
b b e212 b h212 b a h212 h212
b a i221 b l221 a b l221 l221
b b m222 b p222 b b p222 p222
c a a311 c d311 a a d311 d311
c b e312 c h312 b a h312 h312
c a i321 c l321 a b l321 l321
c b m322 c p322 b b p322 p322
d a a411 d d411 a a d411 d411
d b e412 d h412 b a h412 h412
d a i421 d l421 a b l421 l421
d b m422 d p422 b b p422 p422
select min(a2) from t1 group by a1;
min(a2)
a
a
a
a
select a2, min(c), max(c) from t1 group by a1,a2,b;
a2 min(c) max(c)
a a111 d111
a e112 h112
b i121 l121
b m122 p122
a a211 d211
a e212 h212
b i221 l221
b m222 p222
a a311 d311
a e312 h312
b i321 l321
b m322 p322
a a411 d411
a e412 h412
b i421 l421
b m422 p422
explain select a1,a2,b,min(c),max(c) from t1 where a1 < 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-13 12:08:08 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t1 where a1 >= 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select a1, max(c) from t1 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where a1 >= 'c' or a2 < 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 17 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
explain select a1,min(c),max(c) from t1 where a1 >= 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select a1, max(c) from t1 where a1 in ('a','b','d') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-13 12:08:08 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where a1 < 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where a1 < 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where a1 >= 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1, max(c) from t2 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where a1 >= 'c' or a2 < 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,min(c),max(c) from t2 where a1 >= 'b' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1, max(c) from t2 where a1 in ('a','b','d') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
select a1,a2,b,min(c),max(c) from t1 where a1 < 'd' group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
select a1,a2,b,min(c),max(c) from t1 where a1 >= 'b' group by a1,a2,b;
a1 a2 b min(c) max(c)
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t1 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
a1 a2 b max(c)
a a a d111
a a b h112
a b a l121
a b b p122
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
select a1, max(c) from t1 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
a1 max(c)
a d111
a h112
a l121
a p122
c d311
c h312
c l321
c p322
d d411
d h412
d l421
d p422
select a1,a2,b,min(c),max(c) from t1 where a1 >= 'c' or a2 < 'b' group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 d111
a a b e112 h112
b a a a211 d211
b a b e212 h212
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t1 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
a1 a2 b max(c)
b a a d211
b a b h212
b b a l221
b b b p222
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t1 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
a1 a2 b min(c) max(c)
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t1 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
a1 a2 b max(c)
a b a l121
a b b p122
b b a l221
b b b p222
c b a l321
c b b p322
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t1 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
a1 a2 b min(c) max(c)
a b a i121 l121
a b b m122 p122
b b a i221 l221
b b b m222 p222
c b a i321 l321
c b b m322 p322
d b a i421 l421
d b b m422 p422
select a1,min(c),max(c) from t1 where a1 >= 'b' group by a1,a2,b;
a1 min(c) max(c)
b a211 d211
b e212 h212
b i221 l221
b m222 p222
c a311 d311
c e312 h312
c i321 l321
c m322 p322
d a411 d411
d e412 h412
d i421 l421
d m422 p422
select a1, max(c) from t1 where a1 in ('a','b','d') group by a1,a2,b;
a1 max(c)
a d111
a h112
a l121
a p122
b d211
b h212
b l221
b p222
d d411
d h412
d l421
d p422
select a1,a2,b, max(c) from t2 where a1 < 'd' group by a1,a2,b;
a1 a2 b max(c)
a a NULL a999
a a a d111
a a b h112
a b a l121
a b b p122
b a a d211
b a b h212
b b a l221
b b b p222
c a NULL c999
c a a d311
c a b h312
c b a l321
c b b p322
select a1,a2,b,min(c),max(c) from t2 where a1 < 'd' group by a1,a2,b;
a1 a2 b min(c) max(c)
a a NULL a777 a999
a a a a111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a NULL c777 c999
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
select a1,a2,b,min(c),max(c) from t2 where a1 >= 'b' group by a1,a2,b;
a1 a2 b min(c) max(c)
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a NULL c777 c999
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
e a a NULL NULL
e a b NULL NULL
select a1,a2,b, max(c) from t2 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
a1 a2 b max(c)
a a NULL a999
a a a d111
a a b h112
a b a l121
a b b p122
c a NULL c999
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
e a a NULL
e a b NULL
select a1, max(c) from t2 where a1 >= 'c' or a1 < 'b' group by a1,a2,b;
a1 max(c)
a a999
a d111
a h112
a l121
a p122
c c999
c d311
c h312
c l321
c p322
d d411
d h412
d l421
d p422
e NULL
e NULL
select a1,a2,b,min(c),max(c) from t2 where a1 >= 'c' or a2 < 'b' group by a1,a2,b;
a1 a2 b min(c) max(c)
a a NULL a777 a999
a a a a111 d111
a a b e112 h112
b a a a211 d211
b a b e212 h212
c a NULL c777 c999
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
e a a NULL NULL
e a b NULL NULL
select a1,a2,b, max(c) from t2 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
a1 a2 b max(c)
b a a d211
b a b h212
b b a l221
b b b p222
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t2 where a1 = 'z' or a1 = 'b' or a1 = 'd' group by a1,a2,b;
a1 a2 b min(c) max(c)
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t2 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
a1 a2 b max(c)
a b a l121
a b b p122
b b a l221
b b b p222
c b a l321
c b b p322
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t2 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') group by a1,a2,b;
a1 a2 b min(c) max(c)
a b a i121 l121
a b b m122 p122
b b a i221 l221
b b b m222 p222
c b a i321 l321
c b b m322 p322
d b a i421 l421
d b b m422 p422
select a1,min(c),max(c) from t2 where a1 >= 'b' group by a1,a2,b;
a1 min(c) max(c)
b a211 d211
b e212 h212
b i221 l221
b m222 p222
c c777 c999
c a311 d311
c e312 h312
c i321 l321
c m322 p322
d a411 d411
d e412 h412
d i421 l421
d m422 p422
e NULL NULL
e NULL NULL
select a1, max(c) from t2 where a1 in ('a','b','d') group by a1,a2,b;
a1 max(c)
a a999
a d111
a h112
a l121
a p122
b d211
b h212
b l221
b p222
d d411
d h412
d l421
d p422
explain select a1,a2,b,max(c),min(c) from t1 where (a2 = 'a') and (b = 'b') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 5 Using where; Using index for group-by
explain select a1,max(c),min(c) from t1 where (a2 = 'a') and (b = 'b') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 5 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where (b = 'b') group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 9 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (b = 'b') group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 9 Using where; Using index for group-by
explain select a1,a2, max(c) from t1 where (b = 'b') group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 9 Using where; Using index for group-by
explain select a1,a2,b,max(c),min(c) from t2 where (a2 = 'a') and (b = 'b') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 163 NULL 5 Using where; Using index for group-by
explain select a1,max(c),min(c) from t2 where (a2 = 'a') and (b = 'b') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 163 NULL 5 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t2 where (b = 'b') group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 146 NULL 10 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t2 where (b = 'b') group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 163 NULL 10 Using where; Using index for group-by
explain select a1,a2, max(c) from t2 where (b = 'b') group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 146 NULL 10 Using where; Using index for group-by
explain select a1,a2,b,max(c),min(c) from t3 where (a2 = 'a') and (b = 'b') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range NULL idx_t3_1 6 NULL 4 Using where; Using index for group-by
explain select a1,max(c),min(c) from t3 where (a2 = 'a') and (b = 'b') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range NULL idx_t3_1 6 NULL 4 Using where; Using index for group-by
select a1,a2,b,max(c),min(c) from t1 where (a2 = 'a') and (b = 'b') group by a1;
a1 a2 b max(c) min(c)
a a b h112 e112
b a b h212 e212
c a b h312 e312
d a b h412 e412
select a1,max(c),min(c) from t1 where (a2 = 'a') and (b = 'b') group by a1;
a1 max(c) min(c)
a h112 e112
b h212 e212
c h312 e312
d h412 e412
select a1,a2,b, max(c) from t1 where (b = 'b') group by a1,a2;
a1 a2 b max(c)
a a b h112
a b b p122
b a b h212
b b b p222
c a b h312
c b b p322
d a b h412
d b b p422
select a1,a2,b,min(c),max(c) from t1 where (b = 'b') group by a1,a2;
a1 a2 b min(c) max(c)
a a b e112 h112
a b b m122 p122
b a b e212 h212
b b b m222 p222
c a b e312 h312
c b b m322 p322
d a b e412 h412
d b b m422 p422
select a1,a2, max(c) from t1 where (b = 'b') group by a1,a2;
a1 a2 max(c)
a a h112
a b p122
b a h212
b b p222
c a h312
c b p322
d a h412
d b p422
select a1,a2,b,max(c),min(c) from t2 where (a2 = 'a') and (b = 'b') group by a1;
a1 a2 b max(c) min(c)
a a b h112 e112
b a b h212 e212
c a b h312 e312
d a b h412 e412
e a b NULL NULL
select a1,max(c),min(c) from t2 where (a2 = 'a') and (b = 'b') group by a1;
a1 max(c) min(c)
a h112 e112
b h212 e212
c h312 e312
d h412 e412
e NULL NULL
select a1,a2,b, max(c) from t2 where (b = 'b') group by a1,a2;
a1 a2 b max(c)
a a b h112
a b b p122
b a b h212
b b b p222
c a b h312
c b b p322
d a b h412
d b b p422
e a b NULL
select a1,a2,b,min(c),max(c) from t2 where (b = 'b') group by a1,a2;
a1 a2 b min(c) max(c)
a a b e112 h112
a b b m122 p122
b a b e212 h212
b b b m222 p222
c a b e312 h312
c b b m322 p322
d a b e412 h412
d b b m422 p422
e a b NULL NULL
select a1,a2, max(c) from t2 where (b = 'b') group by a1,a2;
a1 a2 max(c)
a a h112
a b p122
b a h212
b b p222
c a h312
c b p322
d a h412
d b p422
e a NULL
select a1,a2,b,max(c),min(c) from t3 where (a2 = 'a') and (b = 'b') group by a1;
a1 a2 b max(c) min(c)
a a b h112 e112
b a b h212 e212
c a b h312 e312
select a1,max(c),min(c) from t3 where (a2 = 'a') and (b = 'b') group by a1;
a1 max(c) min(c)
a h112 e112
b h212 e212
c h312 e312
explain select a1,a2,b,min(c) from t2 where (a2 = 'a') and b is NULL group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 163 NULL 5 Using where; Using index for group-by
explain select a1,a2,b,max(c) from t2 where (a2 = 'a') and b is NULL group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 146 NULL 5 Using where; Using index for group-by
explain select a1,a2,b,min(c) from t2 where b is NULL group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 163 NULL 10 Using where; Using index for group-by
explain select a1,a2,b,max(c) from t2 where b is NULL group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 146 NULL 10 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t2 where b is NULL group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 163 NULL 10 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t2 where b is NULL group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL idx_t2_1 163 NULL 10 Using where; Using index for group-by
select a1,a2,b,min(c) from t2 where (a2 = 'a') and b is NULL group by a1;
a1 a2 b min(c)
a a NULL a777
c a NULL c777
select a1,a2,b,max(c) from t2 where (a2 = 'a') and b is NULL group by a1;
a1 a2 b max(c)
a a NULL a999
c a NULL c999
select a1,a2,b,min(c) from t2 where b is NULL group by a1,a2;
a1 a2 b min(c)
a a NULL a777
c a NULL c777
select a1,a2,b,max(c) from t2 where b is NULL group by a1,a2;
a1 a2 b max(c)
a a NULL a999
c a NULL c999
select a1,a2,b,min(c),max(c) from t2 where b is NULL group by a1,a2;
a1 a2 b min(c) max(c)
a a NULL a777 a999
c a NULL c777 c999
select a1,a2,b,min(c),max(c) from t2 where b is NULL group by a1,a2;
a1 a2 b min(c) max(c)
a a NULL a777 a999
c a NULL c777 c999
explain select a1,a2,b, max(c) from t1 where (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t1 range NULL idx_t1_1 147 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t1 where (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where (c > 'f123') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (c > 'f123') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where (c < 'a0') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (c < 'a0') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where (c < 'k321') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (c < 'k321') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t1 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
Backport of:
revno: 2876.47.174
revision-id: jorgen.loland@oracle.com-20110519120355-qn7eprkad9jqwu5j
parent: mayank.prasad@oracle.com-20110518143645-bdxv4udzrmqsjmhq
committer: Jorgen Loland <jorgen.loland@oracle.com>
branch nick: mysql-trunk-11765831
timestamp: Thu 2011-05-19 14:03:55 +0200
message:
BUG#11765831: 'RANGE ACCESS' MAY INCORRECTLY FILTER
AWAY QUALIFYING ROWS
The problem was that the ranges created when OR'ing two
conditions could be incorrect. Without the bugfix,
"I <> 6 OR (I <> 8 AND J = 5)" would create these ranges:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I < 8",
"8 <= I <= 8 AND 5 <= J <= 5",
"8 < I"
While the correct ranges is
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I"
The problem occurs when key_or() ORs
(1) "NULL < I < 6, 6 <= I <= 6 AND 5 <= J <= 5, 6 < I" with
(2) "8 < I AND 5 <= J <= 5"
The reason for the bug is that in key_or(), SEL_ARG *tmp is
used to point to the range in (1) above that is merged with
(2) while key1 points to the root of the red-black tree of
(1). When merging (1) and (2), tmp refers to the "6 < I"
part whereas the root is the "6 <= ... AND 5 <= J <= 5" part.
key_or() decides that the tmp range needs to be split into
"6 < I < 8, 8 <= I <= 8, 8 < I", in which next_key_part of the
second range should be that of tmp. However, next_key_part is
set to key1->next_key_part ("5 <= J <= 5") instead of
tmp->next_key_part (empty). Fixing this gives the correct but
not optimal ranges:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I < 8",
"8 <= I <= 8",
"8 < I"
A second problem can be seen above: key_or() may create
adjacent ranges that could be replaced with a single range.
Fixes for this is also included in the patch so that the range
above becomes correct AND optimal:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I"
Merging adjacent ranges like this gives a slightly lower cost
estimate for the range access.
2011-08-05 22:01:49 +04:00
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t1 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
Backport of:
revno: 2876.47.174
revision-id: jorgen.loland@oracle.com-20110519120355-qn7eprkad9jqwu5j
parent: mayank.prasad@oracle.com-20110518143645-bdxv4udzrmqsjmhq
committer: Jorgen Loland <jorgen.loland@oracle.com>
branch nick: mysql-trunk-11765831
timestamp: Thu 2011-05-19 14:03:55 +0200
message:
BUG#11765831: 'RANGE ACCESS' MAY INCORRECTLY FILTER
AWAY QUALIFYING ROWS
The problem was that the ranges created when OR'ing two
conditions could be incorrect. Without the bugfix,
"I <> 6 OR (I <> 8 AND J = 5)" would create these ranges:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I < 8",
"8 <= I <= 8 AND 5 <= J <= 5",
"8 < I"
While the correct ranges is
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I"
The problem occurs when key_or() ORs
(1) "NULL < I < 6, 6 <= I <= 6 AND 5 <= J <= 5, 6 < I" with
(2) "8 < I AND 5 <= J <= 5"
The reason for the bug is that in key_or(), SEL_ARG *tmp is
used to point to the range in (1) above that is merged with
(2) while key1 points to the root of the red-black tree of
(1). When merging (1) and (2), tmp refers to the "6 < I"
part whereas the root is the "6 <= ... AND 5 <= J <= 5" part.
key_or() decides that the tmp range needs to be split into
"6 < I < 8, 8 <= I <= 8, 8 < I", in which next_key_part of the
second range should be that of tmp. However, next_key_part is
set to key1->next_key_part ("5 <= J <= 5") instead of
tmp->next_key_part (empty). Fixing this gives the correct but
not optimal ranges:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I < 8",
"8 <= I <= 8",
"8 < I"
A second problem can be seen above: key_or() may create
adjacent ranges that could be replaced with a single range.
Fixes for this is also included in the patch so that the range
above becomes correct AND optimal:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I"
Merging adjacent ranges like this gives a slightly lower cost
estimate for the range access.
2011-08-05 22:01:49 +04:00
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t1 where (c > 'b111') and (c <= 'g112') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (c < 'c5') or (c = 'g412') or (c = 'k421') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where ((c > 'b111') and (c <= 'g112')) or ((c > 'd000') and (c <= 'i110')) group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (c between 'b111' and 'g112') or (c between 'd000' and 'i110') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b, max(c) from t2 where (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where (c > 'f123') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c > 'f123') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where (c < 'a0') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c < 'a0') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where (c < 'k321') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c < 'k321') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b, max(c) from t2 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
Backport of:
revno: 2876.47.174
revision-id: jorgen.loland@oracle.com-20110519120355-qn7eprkad9jqwu5j
parent: mayank.prasad@oracle.com-20110518143645-bdxv4udzrmqsjmhq
committer: Jorgen Loland <jorgen.loland@oracle.com>
branch nick: mysql-trunk-11765831
timestamp: Thu 2011-05-19 14:03:55 +0200
message:
BUG#11765831: 'RANGE ACCESS' MAY INCORRECTLY FILTER
AWAY QUALIFYING ROWS
The problem was that the ranges created when OR'ing two
conditions could be incorrect. Without the bugfix,
"I <> 6 OR (I <> 8 AND J = 5)" would create these ranges:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I < 8",
"8 <= I <= 8 AND 5 <= J <= 5",
"8 < I"
While the correct ranges is
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I"
The problem occurs when key_or() ORs
(1) "NULL < I < 6, 6 <= I <= 6 AND 5 <= J <= 5, 6 < I" with
(2) "8 < I AND 5 <= J <= 5"
The reason for the bug is that in key_or(), SEL_ARG *tmp is
used to point to the range in (1) above that is merged with
(2) while key1 points to the root of the red-black tree of
(1). When merging (1) and (2), tmp refers to the "6 < I"
part whereas the root is the "6 <= ... AND 5 <= J <= 5" part.
key_or() decides that the tmp range needs to be split into
"6 < I < 8, 8 <= I <= 8, 8 < I", in which next_key_part of the
second range should be that of tmp. However, next_key_part is
set to key1->next_key_part ("5 <= J <= 5") instead of
tmp->next_key_part (empty). Fixing this gives the correct but
not optimal ranges:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I < 8",
"8 <= I <= 8",
"8 < I"
A second problem can be seen above: key_or() may create
adjacent ranges that could be replaced with a single range.
Fixes for this is also included in the patch so that the range
above becomes correct AND optimal:
"NULL < I < 6",
"6 <= I <= 6 AND 5 <= J <= 5",
"6 < I"
Merging adjacent ranges like this gives a slightly lower cost
estimate for the range access.
2011-08-05 22:01:49 +04:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c > 'b111') and (c <= 'g112') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (c < 'c5') or (c = 'g412') or (c = 'k421') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where ((c > 'b111') and (c <= 'g112')) or ((c > 'd000') and (c <= 'i110')) group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
select a1,a2,b, max(c) from t1 where (c > 'b1') group by a1,a2,b;
a1 a2 b max(c)
a a a d111
a a b h112
a b a l121
a b b p122
b a a d211
b a b h212
b b a l221
b b b p222
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t1 where (c > 'b1') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a b111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a b211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a b311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a b411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t1 where (c > 'f123') group by a1,a2,b;
a1 a2 b max(c)
a a b h112
a b a l121
a b b p122
b a b h212
b b a l221
b b b p222
c a b h312
c b a l321
c b b p322
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t1 where (c > 'f123') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a b g112 h112
a b a i121 l121
a b b m122 p122
b a b f212 h212
b b a i221 l221
b b b m222 p222
c a b f312 h312
c b a i321 l321
c b b m322 p322
d a b f412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t1 where (c < 'a0') group by a1,a2,b;
a1 a2 b max(c)
select a1,a2,b,min(c),max(c) from t1 where (c < 'a0') group by a1,a2,b;
a1 a2 b min(c) max(c)
select a1,a2,b, max(c) from t1 where (c < 'k321') group by a1,a2,b;
a1 a2 b max(c)
a a a d111
a a b h112
a b a k121
b a a d211
b a b h212
b b a k221
c a a d311
c a b h312
c b a j321
d a a d411
d a b h412
d b a j421
select a1,a2,b,min(c),max(c) from t1 where (c < 'k321') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 d111
a a b e112 h112
a b a i121 k121
b a a a211 d211
b a b e212 h212
b b a i221 k221
c a a a311 d311
c a b e312 h312
c b a i321 j321
d a a a411 d411
d a b e412 h412
d b a i421 j421
select a1,a2,b, max(c) from t1 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
a1 a2 b max(c)
a a a d111
a a b h112
a b a l121
a b b p122
b a a d211
b a b h212
b b a l221
b b b p222
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t1 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a b111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a b211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a b311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a b411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t1 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
a1 a2 b max(c)
a a a d111
a a b h112
a b a l121
a b b p122
b a a d211
b a b h212
b b a l221
b b b p222
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t1 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b,min(c),max(c) from t1 where (c > 'b111') and (c <= 'g112') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a c111 d111
a a b e112 g112
b a a b211 d211
b a b e212 f212
c a a b311 d311
c a b e312 f312
d a a b411 d411
d a b e412 f412
select a1,a2,b,min(c),max(c) from t1 where (c < 'c5') or (c = 'g412') or (c = 'k421') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 c111
b a a a211 c211
c a a a311 c311
d a a a411 c411
d a b g412 g412
d b a k421 k421
select a1,a2,b,min(c),max(c) from t1 where ((c > 'b111') and (c <= 'g112')) or ((c > 'd000') and (c <= 'i110')) group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a c111 d111
a a b e112 h112
b a a b211 d211
b a b e212 h212
c a a b311 d311
c a b e312 h312
d a a b411 d411
d a b e412 h412
select a1,a2,b,min(c),max(c) from t1 where (c between 'b111' and 'g112') or (c between 'd000' and 'i110') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a b111 d111
a a b e112 h112
b a a b211 d211
b a b e212 h212
c a a b311 d311
c a b e312 h312
d a a b411 d411
d a b e412 h412
select a1,a2,b, max(c) from t2 where (c > 'b1') group by a1,a2,b;
a1 a2 b max(c)
a a a d111
a a b h112
a b a l121
a b b p122
b a a d211
b a b h212
b b a l221
b b b p222
c a NULL c999
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t2 where (c > 'b1') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a b111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a b211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a NULL c777 c999
c a a b311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a b411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t2 where (c > 'f123') group by a1,a2,b;
a1 a2 b max(c)
a a b h112
a b a l121
a b b p122
b a b h212
b b a l221
b b b p222
c a b h312
c b a l321
c b b p322
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t2 where (c > 'f123') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a b g112 h112
a b a i121 l121
a b b m122 p122
b a b f212 h212
b b a i221 l221
b b b m222 p222
c a b f312 h312
c b a i321 l321
c b b m322 p322
d a b f412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t2 where (c < 'a0') group by a1,a2,b;
a1 a2 b max(c)
select a1,a2,b,min(c),max(c) from t2 where (c < 'a0') group by a1,a2,b;
a1 a2 b min(c) max(c)
select a1,a2,b, max(c) from t2 where (c < 'k321') group by a1,a2,b;
a1 a2 b max(c)
a a NULL a999
a a a d111
a a b h112
a b a k121
b a a d211
b a b h212
b b a k221
c a NULL c999
c a a d311
c a b h312
c b a j321
d a a d411
d a b h412
d b a j421
select a1,a2,b,min(c),max(c) from t2 where (c < 'k321') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a NULL a777 a999
a a a a111 d111
a a b e112 h112
a b a i121 k121
b a a a211 d211
b a b e212 h212
b b a i221 k221
c a NULL c777 c999
c a a a311 d311
c a b e312 h312
c b a i321 j321
d a a a411 d411
d a b e412 h412
d b a i421 j421
select a1,a2,b, max(c) from t2 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
a1 a2 b max(c)
a a a d111
a a b h112
a b a l121
a b b p122
b a a d211
b a b h212
b b a l221
b b b p222
c a NULL c999
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t2 where (c < 'a0') or (c > 'b1') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a b111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a b211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a NULL c777 c999
c a a b311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a b411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b, max(c) from t2 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
a1 a2 b max(c)
a a NULL a999
a a a d111
a a b h112
a b a l121
a b b p122
b a a d211
b a b h212
b b a l221
b b b p222
c a NULL c999
c a a d311
c a b h312
c b a l321
c b b p322
d a a d411
d a b h412
d b a l421
d b b p422
select a1,a2,b,min(c),max(c) from t2 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a NULL a777 a999
a a a a111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a NULL c777 c999
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b,min(c),max(c) from t2 where (c > 'b111') and (c <= 'g112') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a c111 d111
a a b e112 g112
b a a b211 d211
b a b e212 f212
c a NULL c777 c999
c a a b311 d311
c a b e312 f312
d a a b411 d411
d a b e412 f412
select a1,a2,b,min(c),max(c) from t2 where (c < 'c5') or (c = 'g412') or (c = 'k421') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a NULL a777 a999
a a a a111 c111
b a a a211 c211
c a a a311 c311
d a a a411 c411
d a b g412 g412
d b a k421 k421
select a1,a2,b,min(c),max(c) from t2 where ((c > 'b111') and (c <= 'g112')) or ((c > 'd000') and (c <= 'i110')) group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a c111 d111
a a b e112 h112
b a a b211 d211
b a b e212 h212
c a NULL c777 c999
c a a b311 d311
c a b e312 h312
d a a b411 d411
d a b e412 h412
2004-11-01 10:12:39 +02:00
explain select a1,a2,b,min(c),max(c) from t1
where exists ( select * from t2 where t2.c = t1.c )
group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL idx_t1_1 163 NULL 128 Using where; Using index
2 DEPENDENT SUBQUERY t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
2011-01-18 00:53:41 +02:00
select a1,a2,b,min(c),max(c) from t1
where exists ( select * from t2 where t2.c = t1.c )
group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
2004-11-01 10:12:39 +02:00
explain select a1,a2,b,min(c),max(c) from t1
where exists ( select * from t2 where t2.c > 'b1' )
group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2011-01-18 00:53:41 +02:00
1 PRIMARY t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
2004-12-06 17:15:54 +02:00
2 SUBQUERY t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
2011-01-18 00:53:41 +02:00
select a1,a2,b,min(c),max(c) from t1
where exists ( select * from t2 where t2.c > 'b1' )
group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a a111 d111
a a b e112 h112
a b a i121 l121
a b b m122 p122
b a a a211 d211
b a b e212 h212
b b a i221 l221
b b b m222 p222
c a a a311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a a411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
explain select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2 where t1.b > 'a' and t2.c > 'b1' )
group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
2 DEPENDENT SUBQUERY t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2 where t1.b > 'a' and t2.c > 'b1' )
group by a1,a2,b;
a1 a2 b c min(c) max(c)
a a b h112 e112 h112
a b b p122 m122 p122
b a b h212 e212 h212
b b b p222 m222 p222
c a b h312 e312 h312
c b b p322 m322 p322
d a b h412 e412 h412
d b b p422 m422 p422
2011-12-15 00:21:15 -08:00
SET @save_optimizer_switch=@@optimizer_switch;
SET optimizer_switch='semijoin_with_cache=off';
2011-01-18 00:53:41 +02:00
explain select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2
where t2.c in (select c from t3 where t3.c > t1.b) and
t2.c > 'b1' )
group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
2 DEPENDENT SUBQUERY t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
2011-11-02 13:48:41 +04:00
2 DEPENDENT SUBQUERY t3 index NULL idx_t3_1 10 NULL 192 Using where; Using index; FirstMatch(t2)
2011-01-18 00:53:41 +02:00
select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2
where t2.c in (select c from t3 where t3.c > t1.b) and
t2.c > 'b1' )
group by a1,a2,b;
a1 a2 b c min(c) max(c)
a a a d111 a111 d111
a a b h112 e112 h112
a b a l121 i121 l121
a b b p122 m122 p122
b a a d211 a211 d211
b a b h212 e212 h212
b b a l221 i221 l221
b b b p222 m222 p222
c a a d311 a311 d311
c a b h312 e312 h312
c b a l321 i321 l321
c b b p322 m322 p322
d a a d411 a411 d411
d a b h412 e412 h412
d b a l421 i421 l421
d b b p422 m422 p422
2011-12-15 00:21:15 -08:00
SET optimizer_switch=@save_optimizer_switch;
2011-01-18 00:53:41 +02:00
explain select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2 where t1.c > 'a' and t2.c > 'b1' )
group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL idx_t1_1 163 NULL 128 Using where; Using index
2 DEPENDENT SUBQUERY t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2 where t1.c > 'a' and t2.c > 'b1' )
group by a1,a2,b;
a1 a2 b c min(c) max(c)
a a a a111 a111 d111
a a b e112 e112 h112
a b a i121 i121 l121
a b b m122 m122 p122
b a a a211 a211 d211
b a b e212 e212 h212
b b a i221 i221 l221
b b b m222 m222 p222
c a a a311 a311 d311
c a b e312 e312 h312
c b a i321 i321 l321
c b b m322 m322 p322
d a a a411 a411 d411
d a b e412 e412 h412
d b a i421 i421 l421
d b b m422 m422 p422
2011-12-15 00:21:15 -08:00
SET @save_optimizer_switch=@@optimizer_switch;
SET optimizer_switch='semijoin_with_cache=off';
2011-01-18 00:53:41 +02:00
explain select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2
where t2.c in (select c from t3 where t3.c > t1.c) and
t2.c > 'b1' )
group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL idx_t1_1 163 NULL 128 Using where; Using index
2 DEPENDENT SUBQUERY t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
2011-11-02 13:48:41 +04:00
2 DEPENDENT SUBQUERY t3 index NULL idx_t3_1 10 NULL 192 Using where; Using index; FirstMatch(t2)
2011-01-18 00:53:41 +02:00
select a1,a2,b,c,min(c), max(c) from t1
where exists ( select * from t2
where t2.c in (select c from t3 where t3.c > t1.c) and
t2.c > 'b1' )
group by a1,a2,b;
a1 a2 b c min(c) max(c)
a a a a111 a111 d111
a a b e112 e112 h112
a b a i121 i121 l121
a b b m122 m122 p122
b a a a211 a211 d211
b a b e212 e212 h212
b b a i221 i221 l221
b b b m222 m222 p222
c a a a311 a311 d311
c a b e312 e312 h312
c b a i321 i321 l321
c b b m322 m322 o322
d a a a411 a411 d411
d a b e412 e412 h412
d b a i421 i421 l421
d b b m422 m422 o422
2011-12-15 00:21:15 -08:00
SET optimizer_switch=@save_optimizer_switch;
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t1 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (a1 >= 'c' or a2 < 'b') and (c > 'b111') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t1 where (a2 >= 'b') and (b = 'a') and (c > 'b111') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c) from t1 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c < 'h112') or (c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122')) group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 163 NULL 14 Using where; Using index for group-by
explain select a1,a2,b,min(c) from t1 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122') or (c < 'h112') or (c = 'c111')) group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 163 NULL 14 Using where; Using index for group-by
explain select a1,a2,b,min(c) from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select a1,a2,b,min(c) from t1 where (ord(a1) > 97) and (ord(a2) + ord(a1) > 194) and (b = 'c') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,min(c),max(c) from t2 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (a1 >= 'c' or a2 < 'b') and (c > 'b111') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c),max(c) from t2 where (a2 >= 'b') and (b = 'a') and (c > 'b111') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c) from t2 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c < 'h112') or (c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122')) group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c) from t2 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122') or (c < 'h112') or (c = 'c111')) group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,min(c) from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-30 20:54:37 +04:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 163 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
select a1,a2,b,min(c),max(c) from t1 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a b e112 h112
b a b e212 h212
c a b e312 h312
c b b m322 p322
d a b e412 h412
d b b m422 p422
select a1,a2,b,min(c),max(c) from t1 where (a1 >= 'c' or a2 < 'b') and (c > 'b111') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a c111 d111
a a b e112 h112
b a a b211 d211
b a b e212 h212
c a a b311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a b411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b,min(c),max(c) from t1 where (a2 >= 'b') and (b = 'a') and (c > 'b111') group by a1,a2,b;
a1 a2 b min(c) max(c)
a b a i121 l121
b b a i221 l221
c b a i321 l321
d b a i421 l421
select a1,a2,b,min(c) from t1 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c < 'h112') or (c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122')) group by a1,a2,b;
a1 a2 b min(c)
b b a k221
c b a k321
d b a k421
select a1,a2,b,min(c) from t1 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122') or (c < 'h112') or (c = 'c111')) group by a1,a2,b;
a1 a2 b min(c)
b b a k221
c b a k321
d b a k421
select a1,a2,b,min(c) from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
a1 a2 b min(c)
select a1,a2,b,min(c) from t1 where (ord(a1) > 97) and (ord(a2) + ord(a1) > 194) and (b = 'c') group by a1,a2,b;
a1 a2 b min(c)
select a1,a2,b,min(c),max(c) from t2 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a b e112 h112
b a b e212 h212
c a b e312 h312
c b b m322 p322
d a b e412 h412
d b b m422 p422
e a b NULL NULL
select a1,a2,b,min(c),max(c) from t2 where (a1 >= 'c' or a2 < 'b') and (c > 'b111') group by a1,a2,b;
a1 a2 b min(c) max(c)
a a a c111 d111
a a b e112 h112
b a a b211 d211
b a b e212 h212
c a NULL c777 c999
c a a b311 d311
c a b e312 h312
c b a i321 l321
c b b m322 p322
d a a b411 d411
d a b e412 h412
d b a i421 l421
d b b m422 p422
select a1,a2,b,min(c),max(c) from t2 where (a2 >= 'b') and (b = 'a') and (c > 'b111') group by a1,a2,b;
a1 a2 b min(c) max(c)
a b a i121 l121
b b a i221 l221
c b a i321 l321
d b a i421 l421
select a1,a2,b,min(c) from t2 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c < 'h112') or (c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122')) group by a1,a2,b;
a1 a2 b min(c)
b b a k221
c b a k321
d b a k421
select a1,a2,b,min(c) from t2 where ((a1 > 'a') or (a1 < '9')) and ((a2 >= 'b') and (a2 < 'z')) and (b = 'a') and ((c = 'j121') or (c > 'k121' and c < 'm122') or (c > 'o122') or (c < 'h112') or (c = 'c111')) group by a1,a2,b;
a1 a2 b min(c)
b b a k221
c b a k321
d b a k421
select a1,a2,b,min(c) from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
a1 a2 b min(c)
explain select a1,a2,b from t1 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 17 Using where; Using index for group-by
explain select a1,a2,b from t1 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
explain select a1,a2,b,c from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select a1,a2,b from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select a1,a2,b from t2 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b from t2 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,c from t2 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 index NULL idx_t2_1 163 NULL # Using where; Using index
2004-08-27 16:37:13 +03:00
explain select a1,a2,b from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
select a1,a2,b from t1 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
a1 a2 b
a a b
b a b
c a b
c b b
d a b
d b b
select a1,a2,b from t1 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
a1 a2 b
a b a
b b a
c b a
d b a
select a1,a2,b,c from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
a1 a2 b c
a b a i121
select a1,a2,b from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
a1 a2 b
select a1,a2,b from t2 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
a1 a2 b
a a b
b a b
c a b
c b b
d a b
d b b
e a b
select a1,a2,b from t2 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
a1 a2 b
a b a
b b a
c b a
d b a
select a1,a2,b,c from t2 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
a1 a2 b c
2005-05-18 15:40:34 -07:00
a b a i121
2004-08-27 16:37:13 +03:00
select a1,a2,b from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
a1 a2 b
explain select distinct a1,a2,b from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using index for group-by
explain select distinct a1,a2,b from t1 where (a2 >= 'b') and (b = 'a');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
2006-07-28 21:27:01 +04:00
explain extended select distinct a1,a2,b,c from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 index NULL idx_t1_1 163 NULL 128 50.78 Using where; Using index
Warnings:
Fixed bug mdev-3913.
The wrong result set returned by the left join query from
the bug test case happened due to several inconsistencies
and bugs of the legacy mysql code.
The bug test case uses an execution plan that employs a scan
of a materialized IN subquery from the WHERE condition.
When materializing such an IN- subquery the optimizer injects
additional equalities into the WHERE clause. These equalities
express the constraints imposed by the subquery predicate.
The injected equality of the query in the test case happens
to belong to the same equality class, and a new equality
imposing a condition on the rows of the materialized subquery
is inferred from this class. Simultaneously the multiple
equality is added to the ON expression of the LEFT JOIN
used in the main query.
The inferred equality of the form f1=f2 is taken into account
when optimizing the scan of the rows the temporary table
that is the result of the subquery materialization: only the
values of the field f1 are read from the table into the record
buffer. Meanwhile the inferred equality is removed from the
WHERE conditions altogether as a constraint on the fields
of the temporary table that has been used when filling this table.
This equality is supposed to be removed from the ON expression
when the multiple equalities of the ON expression are converted
into an optimal set of equality predicates. It supposed to be
removed from the ON expression as an equality inferred from only
equalities of the WHERE condition. Yet, it did not happened
due to the following bug in the code.
Erroneously the code tried to build multiple equality for ON
expression twice: the first time, when it called optimize_cond()
for the WHERE condition, the second time, when it called
this function for the HAVING condition. When executing
optimize_con() for the WHERE condition a reference
to the multiple equality of the WHERE condition is set
in the multiple equality of the ON expression. This reference
would allow later to convert multiple equalities of the
ON expression into equality predicates. However the
the second call of build_equal_items() for the ON expression
that happened when optimize_cond() was called for the
HAVING condition reset this reference to NULL.
This bug fix blocks calling build_equal_items() for ON
expressions for the second time. In general, it will be
beneficial for many queries as it removes from ON
expressions any equalities that are to be checked for the
WHERE condition.
The patch also fixes two bugs in the list manipulation
operations and a bug in the function
substitute_for_best_equal_field() that resulted
in passing wrong reference to the multiple equalities
of where conditions when processing multiple
equalities of ON expressions.
The code of substitute_for_best_equal_field() and
the code the helper function eliminate_item_equal()
were also streamlined and cleaned up.
Now the conversion of the multiple equalities into
an optimal set of equality predicates first produces
the sequence of the all equalities processing multiple
equalities one by one, and, only after this, it inserts
the equalities at the beginning of the other conditions.
The multiple changes in the output of EXPLAIN
EXTENDED are mainly the result of this streamlining,
but in some cases is the result of the removal of
unneeded equalities from ON expressions. In
some test cases this removal were reflected in the
output of EXPLAIN resulted in disappearance of
“Using where” in some rows of the execution plans.
2013-02-20 18:01:36 -08:00
Note 1003 select distinct `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`b` = 'a') and (`test`.`t1`.`c` = 'i121') and (`test`.`t1`.`a2` >= 'b'))
2004-08-27 16:37:13 +03:00
explain select distinct a1,a2,b from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select distinct b from t1 where (a2 >= 'b') and (b = 'a');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL idx_t1_2 147 NULL 128 Using where; Using index
explain select distinct a1,a2,b from t2;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using index for group-by
2004-08-27 16:37:13 +03:00
explain select distinct a1,a2,b from t2 where (a2 >= 'b') and (b = 'a');
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by
2006-07-28 21:27:01 +04:00
explain extended select distinct a1,a2,b,c from t2 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 index NULL idx_t2_1 163 NULL 164 50.61 Using where; Using index
Warnings:
Fixed bug mdev-3913.
The wrong result set returned by the left join query from
the bug test case happened due to several inconsistencies
and bugs of the legacy mysql code.
The bug test case uses an execution plan that employs a scan
of a materialized IN subquery from the WHERE condition.
When materializing such an IN- subquery the optimizer injects
additional equalities into the WHERE clause. These equalities
express the constraints imposed by the subquery predicate.
The injected equality of the query in the test case happens
to belong to the same equality class, and a new equality
imposing a condition on the rows of the materialized subquery
is inferred from this class. Simultaneously the multiple
equality is added to the ON expression of the LEFT JOIN
used in the main query.
The inferred equality of the form f1=f2 is taken into account
when optimizing the scan of the rows the temporary table
that is the result of the subquery materialization: only the
values of the field f1 are read from the table into the record
buffer. Meanwhile the inferred equality is removed from the
WHERE conditions altogether as a constraint on the fields
of the temporary table that has been used when filling this table.
This equality is supposed to be removed from the ON expression
when the multiple equalities of the ON expression are converted
into an optimal set of equality predicates. It supposed to be
removed from the ON expression as an equality inferred from only
equalities of the WHERE condition. Yet, it did not happened
due to the following bug in the code.
Erroneously the code tried to build multiple equality for ON
expression twice: the first time, when it called optimize_cond()
for the WHERE condition, the second time, when it called
this function for the HAVING condition. When executing
optimize_con() for the WHERE condition a reference
to the multiple equality of the WHERE condition is set
in the multiple equality of the ON expression. This reference
would allow later to convert multiple equalities of the
ON expression into equality predicates. However the
the second call of build_equal_items() for the ON expression
that happened when optimize_cond() was called for the
HAVING condition reset this reference to NULL.
This bug fix blocks calling build_equal_items() for ON
expressions for the second time. In general, it will be
beneficial for many queries as it removes from ON
expressions any equalities that are to be checked for the
WHERE condition.
The patch also fixes two bugs in the list manipulation
operations and a bug in the function
substitute_for_best_equal_field() that resulted
in passing wrong reference to the multiple equalities
of where conditions when processing multiple
equalities of ON expressions.
The code of substitute_for_best_equal_field() and
the code the helper function eliminate_item_equal()
were also streamlined and cleaned up.
Now the conversion of the multiple equalities into
an optimal set of equality predicates first produces
the sequence of the all equalities processing multiple
equalities one by one, and, only after this, it inserts
the equalities at the beginning of the other conditions.
The multiple changes in the output of EXPLAIN
EXTENDED are mainly the result of this streamlining,
but in some cases is the result of the removal of
unneeded equalities from ON expressions. In
some test cases this removal were reflected in the
output of EXPLAIN resulted in disappearance of
“Using where” in some rows of the execution plans.
2013-02-20 18:01:36 -08:00
Note 1003 select distinct `test`.`t2`.`a1` AS `a1`,`test`.`t2`.`a2` AS `a2`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t2` where ((`test`.`t2`.`b` = 'a') and (`test`.`t2`.`c` = 'i121') and (`test`.`t2`.`a2` >= 'b'))
2004-08-27 16:37:13 +03:00
explain select distinct a1,a2,b from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select distinct b from t2 where (a2 >= 'b') and (b = 'a');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL idx_t2_2 146 NULL 164 Using where; Using index
select distinct a1,a2,b from t1;
a1 a2 b
a a a
a a b
a b a
a b b
b a a
b a b
b b a
b b b
c a a
c a b
c b a
c b b
d a a
d a b
d b a
d b b
select distinct a1,a2,b from t1 where (a2 >= 'b') and (b = 'a');
a1 a2 b
a b a
b b a
c b a
d b a
select distinct a1,a2,b,c from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
a1 a2 b c
a b a i121
select distinct a1,a2,b from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
a1 a2 b
select distinct b from t1 where (a2 >= 'b') and (b = 'a');
b
a
select distinct a1,a2,b from t2;
a1 a2 b
a a NULL
a a a
a a b
a b a
a b b
b a a
b a b
b b a
b b b
c a NULL
c a a
c a b
c b a
c b b
d a a
d a b
d b a
d b b
e a a
e a b
select distinct a1,a2,b from t2 where (a2 >= 'b') and (b = 'a');
a1 a2 b
a b a
b b a
c b a
d b a
select distinct a1,a2,b,c from t2 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
a1 a2 b c
a b a i121
select distinct a1,a2,b from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
a1 a2 b
select distinct b from t2 where (a2 >= 'b') and (b = 'a');
b
a
2004-11-01 10:12:39 +02:00
select distinct t_00.a1
from t1 t_00
where exists ( select * from t2 where a1 = t_00.a1 );
a1
a
b
c
d
2005-02-28 16:20:02 +02:00
select distinct a1,a1 from t1;
a1 a1
a a
b b
c c
d d
select distinct a2,a1,a2,a1 from t1;
a2 a1 a2 a1
a a a a
b a b a
a b a b
b b b b
a c a c
b c b c
a d a d
b d b d
select distinct t1.a1,t2.a1 from t1,t2;
a1 a1
a a
b a
c a
d a
a b
b b
c b
d b
a c
b c
c c
d c
a d
b d
c d
d d
a e
b e
c e
d e
2004-08-27 16:37:13 +03:00
explain select distinct a1,a2,b from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using index for group-by
explain select distinct a1,a2,b from t1 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
explain select distinct a1,a2,b,c from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 17 Using where; Using index for group-by
explain select distinct a1,a2,b from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 Using where; Using index for group-by
explain select distinct b from t1 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by; Using temporary; Using filesort
explain select distinct a1,a2,b from t2;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using index for group-by
2004-08-27 16:37:13 +03:00
explain select distinct a1,a2,b from t2 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select distinct a1,a2,b,c from t2 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 index NULL idx_t2_1 163 NULL # Using where; Using index
2004-08-27 16:37:13 +03:00
explain select distinct a1,a2,b from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range idx_t2_0,idx_t2_1,idx_t2_2 idx_t2_1 146 NULL # Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select distinct b from t2 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-18 15:40:34 -07:00
1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by; Using temporary; Using filesort
2004-08-27 16:37:13 +03:00
select distinct a1,a2,b from t1;
a1 a2 b
a a a
a a b
a b a
a b b
b a a
b a b
b b a
b b b
c a a
c a b
c b a
c b b
d a a
d a b
d b a
d b b
select distinct a1,a2,b from t1 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
a1 a2 b
a b a
b b a
c b a
d b a
select distinct a1,a2,b,c from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
a1 a2 b c
a b a i121
select distinct a1,a2,b from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
a1 a2 b
select distinct b from t1 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
b
a
select distinct a1,a2,b from t2;
a1 a2 b
a a NULL
a a a
a a b
a b a
a b b
b a a
b a b
b b a
b b b
c a NULL
c a a
c a b
c b a
c b b
d a a
d a b
d b a
d b b
e a a
e a b
select distinct a1,a2,b from t2 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
a1 a2 b
a b a
b b a
c b a
d b a
select distinct a1,a2,b,c from t2 where (a2 >= 'b') and (b = 'a') and (c = 'i121') group by a1,a2,b;
a1 a2 b c
2005-05-18 15:40:34 -07:00
a b a i121
2004-08-27 16:37:13 +03:00
select distinct a1,a2,b from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c') group by a1,a2,b;
a1 a2 b
select distinct b from t2 where (a2 >= 'b') and (b = 'a') group by a1,a2,b;
b
a
explain select count(distinct a1,a2,b) from t1 where (a2 >= 'b') and (b = 'a');
id select_type table type possible_keys key key_len ref rows Extra
2009-09-28 10:21:25 +03:00
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select count(distinct a1,a2,b,c) from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
id select_type table type possible_keys key key_len ref rows Extra
2009-09-28 10:21:25 +03:00
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 65 Using where; Using index for group-by (scanning)
2006-07-28 21:27:01 +04:00
explain extended select count(distinct a1,a2,b) from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
id select_type table type possible_keys key key_len ref rows filtered Extra
2009-09-28 10:21:25 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 100.00 Using where; Using index for group-by
2006-07-28 21:27:01 +04:00
Warnings:
2008-02-12 22:09:16 +03:00
Note 1003 select count(distinct `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`) AS `count(distinct a1,a2,b)` from `test`.`t1` where ((`test`.`t1`.`b` = 'c') and (`test`.`t1`.`a1` > 'a') and (`test`.`t1`.`a2` > 'a'))
2004-08-27 16:37:13 +03:00
explain select count(distinct b) from t1 where (a2 >= 'b') and (b = 'a');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL idx_t1_2 147 NULL 128 Using where; Using index
2009-09-28 10:21:25 +03:00
explain extended select 98 + count(distinct a1,a2,b) from t1 where (a1 > 'a') and (a2 > 'a');
2006-07-28 21:27:01 +04:00
id select_type table type possible_keys key key_len ref rows filtered Extra
2009-09-28 10:21:25 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 14 100.00 Using where; Using index for group-by
2006-07-28 21:27:01 +04:00
Warnings:
2009-09-28 10:21:25 +03:00
Note 1003 select (98 + count(distinct `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`)) AS `98 + count(distinct a1,a2,b)` from `test`.`t1` where ((`test`.`t1`.`a1` > 'a') and (`test`.`t1`.`a2` > 'a'))
2004-08-27 16:37:13 +03:00
select count(distinct a1,a2,b) from t1 where (a2 >= 'b') and (b = 'a');
count(distinct a1,a2,b)
4
select count(distinct a1,a2,b,c) from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
count(distinct a1,a2,b,c)
1
select count(distinct a1,a2,b) from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
count(distinct a1,a2,b)
0
select count(distinct b) from t1 where (a2 >= 'b') and (b = 'a');
count(distinct b)
1
2009-09-28 10:21:25 +03:00
select 98 + count(distinct a1,a2,b) from t1 where (a1 > 'a') and (a2 > 'a');
98 + count(distinct a1,a2,b)
2004-08-27 16:37:13 +03:00
104
explain select a1,a2,b, concat(min(c), max(c)) from t1 where a1 < 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-13 12:08:08 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select concat(a1,min(c)),b from t1 where a1 < 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-13 12:08:08 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select concat(a1,min(c)),b,max(c) from t1 where a1 < 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-13 12:08:08 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select concat(a1,a2),b,min(c),max(c) from t1 where a1 < 'd' group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-13 12:08:08 +03:00
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 147 NULL 10 Using where; Using index for group-by
2004-08-27 16:37:13 +03:00
explain select concat(ord(min(b)),ord(max(b))),min(b),max(b) from t1 group by a1,a2;
id select_type table type possible_keys key key_len ref rows Extra
2005-05-30 20:54:37 +04:00
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 9 Using index for group-by
2004-08-27 16:37:13 +03:00
select a1,a2,b, concat(min(c), max(c)) from t1 where a1 < 'd' group by a1,a2,b;
a1 a2 b concat(min(c), max(c))
a a a a111d111
a a b e112h112
a b a i121l121
a b b m122p122
b a a a211d211
b a b e212h212
b b a i221l221
b b b m222p222
c a a a311d311
c a b e312h312
c b a i321l321
c b b m322p322
select concat(a1,min(c)),b from t1 where a1 < 'd' group by a1,a2,b;
concat(a1,min(c)) b
aa111 a
ae112 b
ai121 a
am122 b
ba211 a
be212 b
bi221 a
bm222 b
ca311 a
ce312 b
ci321 a
cm322 b
select concat(a1,min(c)),b,max(c) from t1 where a1 < 'd' group by a1,a2,b;
concat(a1,min(c)) b max(c)
aa111 a d111
ae112 b h112
ai121 a l121
am122 b p122
ba211 a d211
be212 b h212
bi221 a l221
bm222 b p222
ca311 a d311
ce312 b h312
ci321 a l321
cm322 b p322
select concat(a1,a2),b,min(c),max(c) from t1 where a1 < 'd' group by a1,a2,b;
concat(a1,a2) b min(c) max(c)
aa a a111 d111
aa b e112 h112
ab a i121 l121
ab b m122 p122
ba a a211 d211
ba b e212 h212
bb a i221 l221
bb b m222 p222
ca a a311 d311
ca b e312 h312
cb a i321 l321
cb b m322 p322
select concat(ord(min(b)),ord(max(b))),min(b),max(b) from t1 group by a1,a2;
concat(ord(min(b)),ord(max(b))) min(b) max(b)
9798 a b
9798 a b
9798 a b
9798 a b
9798 a b
9798 a b
9798 a b
9798 a b
explain select a1,a2,b,d,min(c),max(c) from t1 group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 128 Using temporary; Using filesort
explain select a1,a2,b,d from t1 group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 128 Using temporary; Using filesort
2006-07-28 21:27:01 +04:00
explain extended select a1,a2,min(b),max(b) from t1
2004-08-27 16:37:13 +03:00
where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') and (c > 'a111') group by a1,a2;
2006-07-28 21:27:01 +04:00
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 130 NULL 76 85.53 Using where; Using index
Warnings:
2008-02-12 22:09:16 +03:00
Note 1003 select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,min(`test`.`t1`.`b`) AS `min(b)`,max(`test`.`t1`.`b`) AS `max(b)` from `test`.`t1` where (((`test`.`t1`.`a1` = 'b') or (`test`.`t1`.`a1` = 'd') or (`test`.`t1`.`a1` = 'a') or (`test`.`t1`.`a1` = 'c')) and (`test`.`t1`.`a2` > 'a') and (`test`.`t1`.`c` > 'a111')) group by `test`.`t1`.`a1`,`test`.`t1`.`a2`
2006-07-28 21:27:01 +04:00
explain extended select a1,a2,b,min(c),max(c) from t1
2004-08-27 16:37:13 +03:00
where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') and (d > 'xy2') group by a1,a2,b;
2006-07-28 21:27:01 +04:00
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL idx_t1_0,idx_t1_1,idx_t1_2 NULL NULL NULL 128 50.78 Using where; Using temporary; Using filesort
Warnings:
2008-02-12 22:09:16 +03:00
Note 1003 select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,`test`.`t1`.`b` AS `b`,min(`test`.`t1`.`c`) AS `min(c)`,max(`test`.`t1`.`c`) AS `max(c)` from `test`.`t1` where (((`test`.`t1`.`a1` = 'b') or (`test`.`t1`.`a1` = 'd') or (`test`.`t1`.`a1` = 'a') or (`test`.`t1`.`a1` = 'c')) and (`test`.`t1`.`a2` > 'a') and (`test`.`t1`.`d` > 'xy2')) group by `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`
2006-07-28 21:27:01 +04:00
explain extended select a1,a2,b,c from t1
2004-08-27 16:37:13 +03:00
where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') and (d > 'xy2') group by a1,a2,b,c;
2006-07-28 21:27:01 +04:00
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL idx_t1_0,idx_t1_1,idx_t1_2 NULL NULL NULL 128 50.78 Using where; Using temporary; Using filesort
Warnings:
2008-02-12 22:09:16 +03:00
Note 1003 select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`a1` = 'b') or (`test`.`t1`.`a1` = 'd') or (`test`.`t1`.`a1` = 'a') or (`test`.`t1`.`a1` = 'c')) and (`test`.`t1`.`a2` > 'a') and (`test`.`t1`.`d` > 'xy2')) group by `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`,`test`.`t1`.`c`
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,max(c),min(c) from t2 where (a2 = 'a') and (b = 'b') or (b < 'b') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
2006-07-28 21:27:01 +04:00
explain extended select a1,a2,b from t1 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') and (c > 'a111') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 130 NULL 76 85.53 Using where; Using index
Warnings:
2008-02-12 22:09:16 +03:00
Note 1003 select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (((`test`.`t1`.`a1` = 'b') or (`test`.`t1`.`a1` = 'd') or (`test`.`t1`.`a1` = 'a') or (`test`.`t1`.`a1` = 'c')) and (`test`.`t1`.`a2` > 'a') and (`test`.`t1`.`c` > 'a111')) group by `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`
2004-09-10 04:45:15 +03:00
explain select a1,a2,min(b),c from t2 where (a2 = 'a') and (c = 'a111') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
select a1,a2,min(b),c from t2 where (a2 = 'a') and (c = 'a111') group by a1;
a1 a2 min(b) c
a a a a111
2004-08-27 16:37:13 +03:00
explain select a1,a2,b,max(c),min(c) from t2 where (a2 = 'a') and (b = 'b') or (b = 'a') group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
explain select a1,a2,b,min(c),max(c) from t2
where (c > 'a000') and (c <= 'd999') and (c like '_8__') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index
explain select a1, a2, b, c, min(d), max(d) from t1 group by a1,a2,b,c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 128 Using temporary; Using filesort
explain select a1,a2,count(a2) from t1 group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows Extra
2007-08-02 12:45:56 -07:00
1 SIMPLE t1 index NULL idx_t1_2 147 NULL 128 Using index
2006-07-28 21:27:01 +04:00
explain extended select a1,a2,count(a2) from t1 where (a1 > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows filtered Extra
2007-08-02 12:45:56 -07:00
1 SIMPLE t1 index idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_2 147 NULL 128 75.00 Using where; Using index
2006-07-28 21:27:01 +04:00
Warnings:
2008-02-12 22:09:16 +03:00
Note 1003 select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,count(`test`.`t1`.`a2`) AS `count(a2)` from `test`.`t1` where (`test`.`t1`.`a1` > 'a') group by `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`
2006-07-28 21:27:01 +04:00
explain extended select sum(ord(a1)) from t1 where (a1 > 'a') group by a1,a2,b;
id select_type table type possible_keys key key_len ref rows filtered Extra
2007-08-02 12:45:56 -07:00
1 SIMPLE t1 index idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_2 147 NULL 128 75.00 Using where; Using index
2006-07-28 21:27:01 +04:00
Warnings:
2008-02-12 22:09:16 +03:00
Note 1003 select sum(ord(`test`.`t1`.`a1`)) AS `sum(ord(a1))` from `test`.`t1` where (`test`.`t1`.`a1` > 'a') group by `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`
2013-08-21 10:51:08 +03:00
create table t4 as select distinct a1, a2, b, c from t1;
alter table t4 add unique index idxt4 (a1, a2, b, c);
explain
select a1, a2, b, min(c) from t4 group by a1, a2, b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t4 index NULL idxt4 163 NULL 64 Using index
select a1, a2, b, min(c) from t4 group by a1, a2, b;
a1 a2 b min(c)
a a a a111
a a b e112
a b a i121
a b b m122
b a a a211
b a b e212
b b a i221
b b b m222
c a a a311
c a b e312
c b a i321
c b b m322
d a a a411
d a b e412
d b a i421
d b b m422
drop table t4;
2006-03-31 12:34:28 +03:00
explain select distinct(a1) from t1 where ord(a2) = 98;
id select_type table type possible_keys key key_len ref rows Extra
2007-08-02 12:45:56 -07:00
1 SIMPLE t1 index NULL idx_t1_2 147 NULL 128 Using where; Using index
2006-03-31 12:34:28 +03:00
select distinct(a1) from t1 where ord(a2) = 98;
a1
a
b
c
d
2005-06-14 12:52:44 +03:00
explain select a1 from t1 where a2 = 'b' group by a1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using where; Using index for group-by
select a1 from t1 where a2 = 'b' group by a1;
a1
a
b
c
d
explain select distinct a1 from t1 where a2 = 'b';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using where; Using index for group-by
select distinct a1 from t1 where a2 = 'b';
a1
a
b
c
d
2006-05-23 16:43:01 +03:00
drop table t1,t2,t3;
2005-11-30 12:52:12 +02:00
create table t1 (c1 int not null,c2 int not null, primary key(c1,c2));
insert into t1 (c1,c2) values
(10,1),(10,2),(10,3),(20,4),(20,5),(20,6),(30,7),(30,8),(30,9);
select distinct c1, c2 from t1 order by c2;
c1 c2
10 1
10 2
10 3
20 4
20 5
20 6
30 7
30 8
30 9
select c1,min(c2) as c2 from t1 group by c1 order by c2;
c1 c2
10 1
20 4
30 7
select c1,c2 from t1 group by c1,c2 order by c2;
c1 c2
10 1
10 2
10 3
20 4
20 5
20 6
30 7
30 8
30 9
drop table t1;
2006-02-06 11:35:13 -08:00
CREATE TABLE t1 (a varchar(5), b int(11), PRIMARY KEY (a,b));
INSERT INTO t1 VALUES ('AA',1), ('AA',2), ('AA',3), ('BB',1), ('AA',4);
OPTIMIZE TABLE t1;
Table Op Msg_type Msg_text
test.t1 optimize status OK
SELECT a FROM t1 WHERE a='AA' GROUP BY a;
a
AA
SELECT a FROM t1 WHERE a='BB' GROUP BY a;
a
BB
EXPLAIN SELECT a FROM t1 WHERE a='AA' GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref PRIMARY PRIMARY 7 const 3 Using where; Using index
EXPLAIN SELECT a FROM t1 WHERE a='BB' GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref PRIMARY PRIMARY 7 const 1 Using where; Using index
SELECT DISTINCT a FROM t1 WHERE a='BB';
a
BB
SELECT DISTINCT a FROM t1 WHERE a LIKE 'B%';
a
BB
SELECT a FROM t1 WHERE a LIKE 'B%' GROUP BY a;
a
BB
DROP TABLE t1;
2006-03-27 12:20:25 +03:00
CREATE TABLE t1 (
a int(11) NOT NULL DEFAULT '0',
b varchar(16) COLLATE latin1_general_ci NOT NULL DEFAULT '',
PRIMARY KEY (a,b)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;
CREATE PROCEDURE a(x INT)
BEGIN
DECLARE rnd INT;
DECLARE cnt INT;
WHILE x > 0 DO
SET rnd= x % 100;
SET cnt = (SELECT COUNT(*) FROM t1 WHERE a = rnd);
INSERT INTO t1(a,b) VALUES (rnd, CAST(cnt AS CHAR));
SET x= x - 1;
END WHILE;
END|
CALL a(1000);
SELECT a FROM t1 WHERE a=0;
a
0
0
0
0
0
0
0
0
0
0
SELECT DISTINCT a FROM t1 WHERE a=0;
a
0
SELECT COUNT(DISTINCT a) FROM t1 WHERE a=0;
COUNT(DISTINCT a)
1
DROP TABLE t1;
DROP PROCEDURE a;
2013-08-21 10:51:08 +03:00
CREATE TABLE t1 (a varchar(64) NOT NULL default '', KEY(a));
BUG#18068: SELECT DISTINCT (with duplicates and covering index)
When converting DISTINCT to GROUP BY where the columns are from the covering
index and they are quoted twice in the SELECT list the optimizer is creating
improper processing sequence. This is because of the fact that the columns
of the covering index are not recognized as such and treated as non-index
columns.
Generally speaking duplicate columns can safely be removed from the GROUP
BY/DISTINCT list because this will not add or remove new rows in the
resulting set. Duplicates can be removed even if they are not consecutive
(as is the case for ORDER BY, where the duplicate columns can be removed
only if they are consecutive).
So we can safely transform "SELECT DISTINCT a,a FROM ... ORDER BY a" to
"SELECT a,a FROM ... GROUP BY a ORDER BY a" instead of
"SELECT a,a FROM .. GROUP BY a,a ORDER BY a". We can even transform
"SELECT DISTINCT a,b,a FROM ... ORDER BY a,b" to
"SELECT a,b,a FROM ... GROUP BY a,b ORDER BY a,b".
The fix to this bug consists of checking for duplicate columns in the SELECT
list when constructing the GROUP BY list in transforming DISTINCT to GROUP
BY and skipping the ones that are already in.
mysql-test/r/distinct.result:
test case for the bug without loose index scan
mysql-test/r/group_min_max.result:
test case for the bug
mysql-test/t/distinct.test:
test case for the bug without loose index scan
mysql-test/t/group_min_max.test:
test case for the bug
sql/sql_select.cc:
duplicates check and removal
2006-05-09 18:13:01 +03:00
INSERT INTO t1 (a) VALUES
(''), ('CENTRAL'), ('EASTERN'), ('GREATER LONDON'),
('NORTH CENTRAL'), ('NORTH EAST'), ('NORTH WEST'), ('SCOTLAND'),
('SOUTH EAST'), ('SOUTH WEST'), ('WESTERN');
EXPLAIN SELECT DISTINCT a,a FROM t1 ORDER BY a;
id select_type table type possible_keys key key_len ref rows Extra
2013-08-21 10:51:08 +03:00
1 SIMPLE t1 range NULL a 66 NULL 6 Using index for group-by
BUG#18068: SELECT DISTINCT (with duplicates and covering index)
When converting DISTINCT to GROUP BY where the columns are from the covering
index and they are quoted twice in the SELECT list the optimizer is creating
improper processing sequence. This is because of the fact that the columns
of the covering index are not recognized as such and treated as non-index
columns.
Generally speaking duplicate columns can safely be removed from the GROUP
BY/DISTINCT list because this will not add or remove new rows in the
resulting set. Duplicates can be removed even if they are not consecutive
(as is the case for ORDER BY, where the duplicate columns can be removed
only if they are consecutive).
So we can safely transform "SELECT DISTINCT a,a FROM ... ORDER BY a" to
"SELECT a,a FROM ... GROUP BY a ORDER BY a" instead of
"SELECT a,a FROM .. GROUP BY a,a ORDER BY a". We can even transform
"SELECT DISTINCT a,b,a FROM ... ORDER BY a,b" to
"SELECT a,b,a FROM ... GROUP BY a,b ORDER BY a,b".
The fix to this bug consists of checking for duplicate columns in the SELECT
list when constructing the GROUP BY list in transforming DISTINCT to GROUP
BY and skipping the ones that are already in.
mysql-test/r/distinct.result:
test case for the bug without loose index scan
mysql-test/r/group_min_max.result:
test case for the bug
mysql-test/t/distinct.test:
test case for the bug without loose index scan
mysql-test/t/group_min_max.test:
test case for the bug
sql/sql_select.cc:
duplicates check and removal
2006-05-09 18:13:01 +03:00
SELECT DISTINCT a,a FROM t1 ORDER BY a;
a a
CENTRAL CENTRAL
EASTERN EASTERN
GREATER LONDON GREATER LONDON
NORTH CENTRAL NORTH CENTRAL
NORTH EAST NORTH EAST
NORTH WEST NORTH WEST
SCOTLAND SCOTLAND
SOUTH EAST SOUTH EAST
SOUTH WEST SOUTH WEST
WESTERN WESTERN
DROP TABLE t1;
2006-07-21 11:59:46 +03:00
CREATE TABLE t1 (id1 INT, id2 INT);
CREATE TABLE t2 (id2 INT, id3 INT, id5 INT);
CREATE TABLE t3 (id3 INT, id4 INT);
CREATE TABLE t4 (id4 INT);
CREATE TABLE t5 (id5 INT, id6 INT);
CREATE TABLE t6 (id6 INT);
INSERT INTO t1 VALUES(1,1);
INSERT INTO t2 VALUES(1,1,1);
INSERT INTO t3 VALUES(1,1);
INSERT INTO t4 VALUES(1);
INSERT INTO t5 VALUES(1,1);
INSERT INTO t6 VALUES(1);
SELECT * FROM
t1
NATURAL JOIN
(t2 JOIN (t3 NATURAL JOIN t4, t5 NATURAL JOIN t6)
ON (t3.id3 = t2.id3 AND t5.id5 = t2.id5));
id2 id1 id3 id5 id4 id3 id6 id5
1 1 1 1 1 1 1 1
SELECT * FROM
t1
NATURAL JOIN
(((t3 NATURAL JOIN t4) join (t5 NATURAL JOIN t6) on t3.id4 = t5.id5) JOIN t2
ON (t3.id3 = t2.id3 AND t5.id5 = t2.id5));
id2 id1 id4 id3 id6 id5 id3 id5
1 1 1 1 1 1 1 1
SELECT * FROM t1 NATURAL JOIN ((t3 join (t5 NATURAL JOIN t6)) JOIN t2);
id2 id1 id3 id4 id6 id5 id3 id5
1 1 1 1 1 1 1 1
SELECT * FROM
(t2 JOIN (t3 NATURAL JOIN t4, t5 NATURAL JOIN t6)
ON (t3.id3 = t2.id3 AND t5.id5 = t2.id5))
NATURAL JOIN
t1;
id2 id3 id5 id4 id3 id6 id5 id1
1 1 1 1 1 1 1 1
SELECT * FROM
(t2 JOIN ((t3 NATURAL JOIN t4) join (t5 NATURAL JOIN t6)))
NATURAL JOIN
t1;
id2 id3 id5 id4 id3 id6 id5 id1
1 1 1 1 1 1 1 1
DROP TABLE t1,t2,t3,t4,t5,t6;
2013-08-21 10:51:08 +03:00
CREATE TABLE t1 (a int, b int, KEY (a,b), KEY b (b));
2006-10-18 17:24:33 -07:00
INSERT INTO t1 VALUES (1,1),(1,2),(1,0),(1,3);
2006-10-16 19:30:19 +03:00
explain SELECT MAX(b), a FROM t1 WHERE b < 2 AND a = 1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
2013-08-21 10:51:08 +03:00
1 SIMPLE t1 range a,b a 10 NULL 1 Using where; Using index for group-by
2006-10-16 19:30:19 +03:00
SELECT MAX(b), a FROM t1 WHERE b < 2 AND a = 1 GROUP BY a;
MAX(b) a
1 1
SELECT MIN(b), a FROM t1 WHERE b > 1 AND a = 1 GROUP BY a;
MIN(b) a
2 1
CREATE TABLE t2 (a int, b int, c int, PRIMARY KEY (a,b,c));
INSERT INTO t2 SELECT a,b,b FROM t1;
explain SELECT MIN(c) FROM t2 WHERE b = 2 and a = 1 and c > 1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
2013-08-21 10:51:08 +03:00
1 SIMPLE t2 ref PRIMARY PRIMARY 8 const,const 1 Using where; Using index
2006-10-16 19:30:19 +03:00
SELECT MIN(c) FROM t2 WHERE b = 2 and a = 1 and c > 1 GROUP BY a;
MIN(c)
2
DROP TABLE t1,t2;
2006-11-28 18:06:47 +02:00
CREATE TABLE t1 (a INT, b INT, INDEX (a,b));
INSERT INTO t1 (a, b) VALUES (1,1), (1,2), (1,3), (1,4), (1,5),
(2,2), (2,3), (2,1), (3,1), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6);
EXPLAIN SELECT max(b), a FROM t1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 5 NULL 8 Using index for group-by
FLUSH STATUS;
SELECT max(b), a FROM t1 GROUP BY a;
max(b) a
5 1
3 2
1 3
6 4
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 8
Handler_read_next 0
EXPLAIN SELECT max(b), a FROM t1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 5 NULL 8 Using index for group-by
FLUSH STATUS;
CREATE TABLE t2 SELECT max(b), a FROM t1 GROUP BY a;
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 8
Handler_read_next 0
FLUSH STATUS;
SELECT * FROM (SELECT max(b), a FROM t1 GROUP BY a) b;
max(b) a
5 1
3 2
1 3
6 4
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 8
Handler_read_next 0
FLUSH STATUS;
(SELECT max(b), a FROM t1 GROUP BY a) UNION
(SELECT max(b), a FROM t1 GROUP BY a);
max(b) a
5 1
3 2
1 3
6 4
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 16
Handler_read_next 0
EXPLAIN (SELECT max(b), a FROM t1 GROUP BY a) UNION
(SELECT max(b), a FROM t1 GROUP BY a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 range NULL a 5 NULL 8 Using index for group-by
2 UNION t1 range NULL a 5 NULL 8 Using index for group-by
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
EXPLAIN SELECT (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) x
FROM t1 AS t1_outer;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1_outer index NULL a 10 NULL 15 Using index
2 SUBQUERY t1 range NULL a 5 NULL 8 Using index for group-by
EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE EXISTS
(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1_outer index NULL a 10 NULL 15 Using index
2012-05-17 13:46:05 +03:00
2 SUBQUERY t1 index NULL a 10 NULL 15 Using index
2006-11-28 18:06:47 +02:00
EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE
(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
id select_type table type possible_keys key key_len ref rows Extra
2012-05-17 13:46:05 +03:00
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2012-08-28 16:03:22 +04:00
2 SUBQUERY t1 range NULL a 5 NULL 8 Using index for group-by
2006-11-28 18:06:47 +02:00
EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE
a IN (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
id select_type table type possible_keys key key_len ref rows Extra
2012-02-24 16:50:22 -08:00
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 8
2011-11-09 15:36:25 +02:00
1 PRIMARY t1_outer ref a a 5 <subquery2>.max(b) 2 Using index
2011-12-05 01:31:42 +04:00
2 MATERIALIZED t1 range NULL a 5 NULL 8 Using index for group-by
2006-11-28 18:06:47 +02:00
EXPLAIN SELECT 1 FROM t1 AS t1_outer GROUP BY a HAVING
a > (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1_outer range NULL a 5 NULL 8 Using index for group-by
2 SUBQUERY t1 range NULL a 5 NULL 8 Using index for group-by
EXPLAIN SELECT 1 FROM t1 AS t1_outer1 JOIN t1 AS t1_outer2
ON t1_outer1.a = (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2)
AND t1_outer1.b = t1_outer2.b;
id select_type table type possible_keys key key_len ref rows Extra
2012-05-17 13:46:05 +03:00
1 PRIMARY t1_outer1 ref a a 5 const 1 Using where; Using index
2010-10-18 13:33:05 -07:00
1 PRIMARY t1_outer2 index NULL a 10 NULL 15 Using where; Using index; Using join buffer (flat, BNL join)
2012-08-28 16:03:22 +04:00
2 SUBQUERY t1 range NULL a 5 NULL 8 Using index for group-by
2006-11-28 18:06:47 +02:00
EXPLAIN SELECT (SELECT (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) x
FROM t1 AS t1_outer) x2 FROM t1 AS t1_outer2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1_outer2 index NULL a 10 NULL 15 Using index
2 SUBQUERY t1_outer index NULL a 10 NULL 15 Using index
3 SUBQUERY t1 range NULL a 5 NULL 8 Using index for group-by
CREATE TABLE t3 LIKE t1;
FLUSH STATUS;
INSERT INTO t3 SELECT a,MAX(b) FROM t1 GROUP BY a;
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 8
Handler_read_next 0
DELETE FROM t3;
FLUSH STATUS;
INSERT INTO t3 SELECT 1, (SELECT MAX(b) FROM t1 GROUP BY a HAVING a < 2)
FROM t1 LIMIT 1;
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 8
Handler_read_next 0
FLUSH STATUS;
DELETE FROM t3 WHERE (SELECT MAX(b) FROM t1 GROUP BY a HAVING a < 2) > 10000;
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 8
Handler_read_next 0
FLUSH STATUS;
DELETE FROM t3 WHERE (SELECT (SELECT MAX(b) FROM t1 GROUP BY a HAVING a < 2) x
FROM t1) > 10000;
2007-11-02 02:36:12 +03:00
ERROR 21000: Subquery returns more than 1 row
2006-11-28 18:06:47 +02:00
SHOW STATUS LIKE 'handler_read__e%';
Variable_name Value
Handler_read_key 8
Handler_read_next 1
DROP TABLE t1,t2,t3;
2007-06-23 23:33:55 -07:00
CREATE TABLE t1 (a int, INDEX idx(a));
INSERT INTO t1 VALUES
(4), (2), (1), (2), (4), (2), (1), (4),
(4), (2), (1), (2), (2), (4), (1), (4);
EXPLAIN SELECT DISTINCT(a) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx 5 NULL 9 Using index for group-by
SELECT DISTINCT(a) FROM t1;
a
1
2
4
EXPLAIN SELECT SQL_BIG_RESULT DISTINCT(a) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL idx 5 NULL 9 Using index for group-by
SELECT SQL_BIG_RESULT DISTINCT(a) FROM t1;
a
1
2
4
DROP TABLE t1;
2007-11-20 16:07:24 +02:00
CREATE TABLE t1 (a INT, b INT);
INSERT INTO t1 (a, b) VALUES (1,1), (1,2), (1,3);
INSERT INTO t1 SELECT a + 1, b FROM t1;
INSERT INTO t1 SELECT a + 2, b FROM t1;
EXPLAIN
SELECT a, MIN(b), MAX(b) FROM t1 GROUP BY a ORDER BY a DESC;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 12 Using temporary; Using filesort
SELECT a, MIN(b), MAX(b) FROM t1 GROUP BY a ORDER BY a DESC;
a MIN(b) MAX(b)
4 1 3
3 1 3
2 1 3
1 1 3
CREATE INDEX break_it ON t1 (a, b);
EXPLAIN
SELECT a, MIN(b), MAX(b) FROM t1 GROUP BY a ORDER BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL break_it 10 NULL 7 Using index for group-by
SELECT a, MIN(b), MAX(b) FROM t1 GROUP BY a ORDER BY a;
a MIN(b) MAX(b)
1 1 3
2 1 3
3 1 3
4 1 3
EXPLAIN
SELECT a, MIN(b), MAX(b) FROM t1 GROUP BY a ORDER BY a DESC;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL break_it 10 NULL 7 Using index for group-by; Using temporary; Using filesort
SELECT a, MIN(b), MAX(b) FROM t1 GROUP BY a ORDER BY a DESC;
a MIN(b) MAX(b)
4 1 3
3 1 3
2 1 3
1 1 3
EXPLAIN
SELECT a, MIN(b), MAX(b), AVG(b) FROM t1 GROUP BY a ORDER BY a DESC;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL break_it 10 NULL 12 Using index
SELECT a, MIN(b), MAX(b), AVG(b) FROM t1 GROUP BY a ORDER BY a DESC;
a MIN(b) MAX(b) AVG(b)
4 1 3 2.0000
3 1 3 2.0000
2 1 3 2.0000
1 1 3 2.0000
DROP TABLE t1;
2013-08-21 10:51:08 +03:00
create table t1 (a int, b int, key (a,b), key `index` (a,b)) engine=MyISAM;
2013-09-27 07:29:36 +03:00
Warnings:
Note 1831 Duplicate index 'index' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
2008-08-27 17:03:17 +04:00
insert into t1 (a,b) values
(0,0),(0,1),(0,2),(0,3),(0,4),(0,5),(0,6),
(0,7),(0,8),(0,9),(0,10),(0,11),(0,12),(0,13),
(1,0),(1,1),(1,2),(1,3),(1,4),(1,5),(1,6),
(1,7),(1,8),(1,9),(1,10),(1,11),(1,12),(1,13),
(2,0),(2,1),(2,2),(2,3),(2,4),(2,5),(2,6),
(2,7),(2,8),(2,9),(2,10),(2,11),(2,12),(2,13),
(3,0),(3,1),(3,2),(3,3),(3,4),(3,5),(3,6),
(3,7),(3,8),(3,9),(3,10),(3,11),(3,12),(3,13);
insert into t1 (a,b) select a, max(b)+1 from t1 where a = 0 group by a;
select * from t1;
a b
0 0
0 1
0 2
0 3
0 4
0 5
0 6
0 7
0 8
0 9
0 10
0 11
0 12
0 13
0 14
1 0
1 1
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
2 0
2 1
2 2
2 3
2 4
2 5
2 6
2 7
2 8
2 9
2 10
2 11
2 12
2 13
3 0
3 1
3 2
3 3
3 4
3 5
3 6
3 7
3 8
3 9
3 10
3 11
3 12
3 13
explain extended select sql_buffer_result a, max(b)+1 from t1 where a = 0 group by a;
2008-08-28 12:54:50 +03:00
id select_type table type possible_keys key key_len ref rows filtered Extra
2013-08-21 10:51:08 +03:00
1 SIMPLE t1 ref a,index a 5 const 15 100.00 Using index; Using temporary
2008-08-27 17:03:17 +04:00
Warnings:
Note 1003 select sql_buffer_result `test`.`t1`.`a` AS `a`,(max(`test`.`t1`.`b`) + 1) AS `max(b)+1` from `test`.`t1` where (`test`.`t1`.`a` = 0) group by `test`.`t1`.`a`
drop table t1;
2009-02-27 15:25:06 +02:00
CREATE TABLE t1 (a int, b int, c int, d int,
KEY foo (c,d,a,b), KEY bar (c,a,b,d));
INSERT INTO t1 VALUES (1, 1, 1, 1), (1, 1, 1, 2), (1, 1, 1, 3), (1, 1, 1, 4);
INSERT INTO t1 SELECT * FROM t1;
INSERT INTO t1 SELECT * FROM t1;
INSERT INTO t1 SELECT a,b,c+1,d FROM t1;
EXPLAIN SELECT DISTINCT c FROM t1 WHERE d=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL foo 10 NULL 9 Using where; Using index for group-by
SELECT DISTINCT c FROM t1 WHERE d=4;
c
1
2
DROP TABLE t1;
2009-06-12 15:38:55 +03:00
#
# Bug #45386: Wrong query result with MIN function in field list,
# WHERE and GROUP BY clause
#
CREATE TABLE t (a INT, b INT, INDEX (a,b));
INSERT INTO t VALUES (2,0), (2,0), (2,1), (2,1);
INSERT INTO t SELECT * FROM t;
# test MIN
#should use range with index for group by
EXPLAIN
SELECT a, MIN(b) FROM t WHERE b <> 0 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t range NULL a 10 NULL 9 Using where; Using index for group-by
#should return 1 row
SELECT a, MIN(b) FROM t WHERE b <> 0 GROUP BY a;
a MIN(b)
2 1
# test MAX
#should use range with index for group by
EXPLAIN
SELECT a, MAX(b) FROM t WHERE b <> 1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t range NULL a 10 NULL 9 Using where; Using index for group-by
#should return 1 row
SELECT a, MAX(b) FROM t WHERE b <> 1 GROUP BY a;
a MAX(b)
2 0
# test 3 ranges and use the middle one
INSERT INTO t SELECT a, 2 FROM t;
#should use range with index for group by
EXPLAIN
SELECT a, MAX(b) FROM t WHERE b > 0 AND b < 2 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t range NULL a 10 NULL 9 Using where; Using index for group-by
#should return 1 row
SELECT a, MAX(b) FROM t WHERE b > 0 AND b < 2 GROUP BY a;
a MAX(b)
2 1
DROP TABLE t;
2009-11-17 17:07:14 +03:00
#
# Bug #48472: Loose index scan inappropriately chosen for some WHERE
# conditions
#
CREATE TABLE t (a INT, b INT, INDEX (a,b));
INSERT INTO t VALUES (2,0), (2,0), (2,1), (2,1);
INSERT INTO t SELECT * FROM t;
SELECT a, MAX(b) FROM t WHERE 0=b+0 GROUP BY a;
a MAX(b)
2 0
DROP TABLE t;
2009-02-27 15:25:06 +02:00
End of 5.0 tests
2009-08-30 11:03:37 +04:00
#
# Bug #46607: Assertion failed: (cond_type == Item::FUNC_ITEM) results in
# server crash
#
CREATE TABLE t (a INT, b INT, INDEX (a,b));
INSERT INTO t VALUES (2,0), (2,0), (2,1), (2,1);
INSERT INTO t SELECT * FROM t;
SELECT a, MAX(b) FROM t WHERE b GROUP BY a;
a MAX(b)
2 1
DROP TABLE t;
2010-02-09 12:53:13 +04:00
CREATE TABLE t1(a INT NOT NULL, b INT NOT NULL, KEY (b));
INSERT INTO t1 VALUES(1,1),(2,1);
ANALYZE TABLE t1;
Table Op Msg_type Msg_text
test.t1 analyze status OK
SELECT 1 AS c, b FROM t1 WHERE b IN (1,2) GROUP BY c, b;
c b
1 1
SELECT a FROM t1 WHERE b=1;
a
1
2
DROP TABLE t1;
2010-03-16 15:51:00 +01:00
#
# Bug#47762: Incorrect result from MIN() when WHERE tests NOT NULL column
# for NULL
#
## Test for NULLs allowed
CREATE TABLE t1 ( a INT, KEY (a) );
INSERT INTO t1 VALUES (1), (2), (3);
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a = NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a = NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a <> NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a <> NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a > NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a > NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a < NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a < NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a <=> NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x No matching min/max row
SELECT MIN( a ) FROM t1 WHERE a <=> NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND 10;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND 10;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN 10 AND NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN 10 AND NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a = (SELECT a FROM t1 WHERE a < 0);
id select_type table type possible_keys key key_len ref rows Extra
2012-05-17 13:46:05 +03:00
x x x x x x x x x Impossible WHERE noticed after reading const tables
2012-08-28 16:03:22 +04:00
x x x x x x x x x Using where; Using index
2010-03-16 15:51:00 +01:00
SELECT MIN( a ) FROM t1 WHERE a = (SELECT a FROM t1 WHERE a < 0);
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x No matching min/max row
SELECT MIN( a ) FROM t1 WHERE a IS NULL;
MIN( a )
NULL
INSERT INTO t1 VALUES (NULL), (NULL);
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a = NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a = NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a <> NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a <> NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a > NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a > NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a < NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a < NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a <=> NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Select tables optimized away
SELECT MIN( a ) FROM t1 WHERE a <=> NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND 10;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND 10;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN 10 AND NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN 10 AND NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a = (SELECT a FROM t1 WHERE a < 0);
id select_type table type possible_keys key key_len ref rows Extra
2012-05-17 13:46:05 +03:00
x x x x x x x x x Impossible WHERE noticed after reading const tables
2012-08-28 16:03:22 +04:00
x x x x x x x x x Using where; Using index
2010-03-16 15:51:00 +01:00
SELECT MIN( a ) FROM t1 WHERE a = (SELECT a FROM t1 WHERE a < 0);
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Select tables optimized away
SELECT MIN( a ) FROM t1 WHERE a IS NULL;
MIN( a )
NULL
DROP TABLE t1;
## Test for NOT NULLs
CREATE TABLE t1 ( a INT NOT NULL PRIMARY KEY);
INSERT INTO t1 VALUES (1), (2), (3);
2010-03-19 09:23:44 +01:00
#
# NULL-safe operator test disabled for non-NULL indexed columns.
#
# See bugs
#
# - Bug#52173: Reading NULL value from non-NULL index gives
# wrong result in embedded server
#
# - Bug#52174: Sometimes wrong plan when reading a MAX value from
# non-NULL index
#
2010-03-16 15:51:00 +01:00
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a = NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a = NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a <> NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a <> NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a > NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a > NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a < NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a < NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND 10;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND 10;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN NULL AND NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a BETWEEN 10 AND NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE noticed after reading const tables
SELECT MIN( a ) FROM t1 WHERE a BETWEEN 10 AND NULL;
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a = (SELECT a FROM t1 WHERE a < 0);
id select_type table type possible_keys key key_len ref rows Extra
2012-05-17 13:46:05 +03:00
x x x x x x x x x Impossible WHERE noticed after reading const tables
2012-08-28 16:03:22 +04:00
x x x x x x x x x Using where; Using index
2010-03-16 15:51:00 +01:00
SELECT MIN( a ) FROM t1 WHERE a = (SELECT a FROM t1 WHERE a < 0);
MIN( a )
NULL
EXPLAIN
SELECT MIN( a ) FROM t1 WHERE a IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
x x x x x x x x x Impossible WHERE
SELECT MIN( a ) FROM t1 WHERE a IS NULL;
MIN( a )
NULL
DROP TABLE t1;
2010-06-11 09:38:29 +02:00
#
# Bug#53859: Valgrind: opt_sum_query(TABLE_LIST*, List<Item>&, Item*) at
# opt_sum.cc:305
#
CREATE TABLE t1 ( a INT, KEY (a) );
INSERT INTO t1 VALUES (1), (2), (3);
SELECT MIN( a ) AS min_a
FROM t1
WHERE a > 1 AND a IS NULL
ORDER BY min_a;
min_a
NULL
DROP TABLE t1;
2013-01-25 14:29:46 +01:00
create table t1 (a int, b varchar(1), key(b,a)) engine=myisam;
insert t1 values (1,'a'),(2,'b'),(3,'c'),(4,'d'),(5,'e'),(6,'f'),(7,'g'),(8,'h'),(null,'i');
select min(a), b from t1 where a=7 or b='z' group by b;
min(a) b
7 g
flush tables;
drop table t1;
2011-12-08 12:05:52 +02:00
#
# LP BUG#888456 Wrong result with DISTINCT , ANY , subquery_cache=off , NOT NULL
#
CREATE TABLE t1 ( a int NOT NULL) ;
INSERT INTO t1 VALUES (28),(29),(9);
CREATE TABLE t2 ( a int, KEY (a)) ;
INSERT INTO t2 VALUES (1),(1),(1),(4),(4),(5),(5),(8),(8),(9);
explain select (select t2.a from t2 where t2.a >= t1.a group by t2.a) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3
2011-12-12 12:36:46 +02:00
2 DEPENDENT SUBQUERY t2 index a a 5 NULL 10 Using where; Using index
2011-12-08 12:05:52 +02:00
select (select t2.a from t2 where t2.a >= t1.a group by t2.a) from t1;
(select t2.a from t2 where t2.a >= t1.a group by t2.a)
NULL
NULL
9
drop table t1, t2;
2011-12-12 12:36:46 +02:00
#
# LP BUG#900375 Wrong result with derived_merge=ON, DISTINCT or GROUP BY, EXISTS
#
CREATE TABLE t1 ( a INT, b INT, KEY (b) );
INSERT INTO t1 VALUES
(100,10),(101,11),(102,12),(103,13),(104,14),
(105,15),(106,16),(107,17),(108,18),(109,19);
EXPLAIN
SELECT alias1.* FROM t1, (SELECT * FROM t1) AS alias1
WHERE EXISTS ( SELECT DISTINCT b FROM t1 WHERE b <= alias1.a ) ;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL b 5 NULL 10 Using index
2011-12-12 13:00:33 +01:00
1 PRIMARY t1 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
2011-12-19 23:05:44 +02:00
3 DEPENDENT SUBQUERY t1 index b b 5 NULL 10 Using where; Using index
2011-12-12 12:36:46 +02:00
SELECT alias1.* FROM t1, (SELECT * FROM t1) AS alias1
WHERE EXISTS ( SELECT DISTINCT b FROM t1 WHERE b <= alias1.a ) ;
a b
100 10
100 10
100 10
100 10
100 10
100 10
100 10
100 10
100 10
100 10
101 11
101 11
101 11
101 11
101 11
101 11
101 11
101 11
101 11
101 11
102 12
102 12
102 12
102 12
102 12
102 12
102 12
102 12
102 12
102 12
103 13
103 13
103 13
103 13
103 13
103 13
103 13
103 13
103 13
103 13
104 14
104 14
104 14
104 14
104 14
104 14
104 14
104 14
104 14
104 14
105 15
105 15
105 15
105 15
105 15
105 15
105 15
105 15
105 15
105 15
106 16
106 16
106 16
106 16
106 16
106 16
106 16
106 16
106 16
106 16
107 17
107 17
107 17
107 17
107 17
107 17
107 17
107 17
107 17
107 17
108 18
108 18
108 18
108 18
108 18
108 18
108 18
108 18
108 18
108 18
109 19
109 19
109 19
109 19
109 19
109 19
109 19
109 19
109 19
109 19
EXPLAIN
SELECT alias1.* FROM t1, t1 AS alias1
WHERE EXISTS ( SELECT DISTINCT b FROM t1 WHERE b <= alias1.a ) ;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL b 5 NULL 10 Using index
2011-12-12 13:00:33 +01:00
1 PRIMARY alias1 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
2011-12-19 23:05:44 +02:00
2 DEPENDENT SUBQUERY t1 index b b 5 NULL 10 Using where; Using index
2011-12-12 12:36:46 +02:00
SELECT alias1.* FROM t1, t1 AS alias1
WHERE EXISTS ( SELECT DISTINCT b FROM t1 WHERE b <= alias1.a ) ;
a b
100 10
100 10
100 10
100 10
100 10
100 10
100 10
100 10
100 10
100 10
101 11
101 11
101 11
101 11
101 11
101 11
101 11
101 11
101 11
101 11
102 12
102 12
102 12
102 12
102 12
102 12
102 12
102 12
102 12
102 12
103 13
103 13
103 13
103 13
103 13
103 13
103 13
103 13
103 13
103 13
104 14
104 14
104 14
104 14
104 14
104 14
104 14
104 14
104 14
104 14
105 15
105 15
105 15
105 15
105 15
105 15
105 15
105 15
105 15
105 15
106 16
106 16
106 16
106 16
106 16
106 16
106 16
106 16
106 16
106 16
107 17
107 17
107 17
107 17
107 17
107 17
107 17
107 17
107 17
107 17
108 18
108 18
108 18
108 18
108 18
108 18
108 18
108 18
108 18
108 18
109 19
109 19
109 19
109 19
109 19
109 19
109 19
109 19
109 19
109 19
drop table t1;
2009-08-30 11:03:37 +04:00
End of 5.1 tests
2009-09-28 10:21:25 +03:00
#
2013-02-28 22:47:29 +01:00
# MDEV-765 lp:825075 - Wrong result with GROUP BY + multipart key + MIN/MAX loose scan
2013-02-04 17:35:48 +02:00
#
CREATE TABLE t1 (a varchar(1), b varchar(1), KEY (b,a));
INSERT INTO t1 VALUES
('0',NULL),('9',NULL),('8','c'),('4','d'),('7','d'),(NULL,'f'),
('7','f'),('8','g'),(NULL,'j');
explain
SELECT max(a) , b FROM t1 WHERE a IS NULL OR b = 'z' GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index b b 8 NULL 9 Using where; Using index
SELECT max(a) , b FROM t1 WHERE a IS NULL OR b = 'z' GROUP BY b;
max(a) b
NULL f
NULL j
explain
SELECT b, min(a) FROM t1 WHERE a = '7' OR b = 'z' GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index b b 8 NULL 9 Using where; Using index
SELECT b, min(a) FROM t1 WHERE a = '7' OR b = 'z' GROUP BY b;
b min(a)
d 7
f 7
explain
SELECT b, min(a) FROM t1 WHERE (a = b OR b = 'd' OR b is NULL) GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index b b 8 NULL 9 Using where; Using index
SELECT b, min(a) FROM t1 WHERE (a = b OR b = 'd' OR b is NULL) GROUP BY b;
b min(a)
NULL 0
d 4
explain
SELECT b, min(a) FROM t1 WHERE a > ('0' = b) AND b = 'z' GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref b b 4 const 1 Using where; Using index
SELECT b, min(a) FROM t1 WHERE a > ('0' = b) AND b = 'z' GROUP BY b;
b min(a)
explain
SELECT b, min(a) FROM t1 WHERE a > '0' AND (b < (a = '7')) GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL b 8 NULL 9 Using where; Using index
SELECT b, min(a) FROM t1 WHERE a > '0' AND (b < (a = '7')) GROUP BY b;
b min(a)
d 7
f 7
2013-02-28 22:47:29 +01:00
Warnings:
Warning 1292 Truncated incorrect DOUBLE value: 'c'
Warning 1292 Truncated incorrect DOUBLE value: 'd'
Warning 1292 Truncated incorrect DOUBLE value: 'd'
Warning 1292 Truncated incorrect DOUBLE value: 'f'
Warning 1292 Truncated incorrect DOUBLE value: 'g'
2013-02-04 17:35:48 +02:00
explain
SELECT b, min(a) FROM t1 WHERE (a > '0' AND (a > '1' OR b = 'd')) GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index b b 8 NULL 9 Using where; Using index
SELECT b, min(a) FROM t1 WHERE (a > '0' AND (a > '1' OR b = 'd')) GROUP BY b;
b min(a)
NULL 9
c 8
d 4
f 7
g 8
drop table t1;
2013-02-13 11:58:16 +02:00
#
# MDEV-4140 Wrong result with GROUP BY + multipart key + MIN/MAX loose scan and a subquery
#
CREATE TABLE t1 (a int, b int, KEY (b, a)) ;
INSERT INTO t1 VALUES (0,99),(9,99),(4,0),(7,0),(99,0),(7,0),(8,0),(99,0),(1,0);
CREATE TABLE t2 (c int) ;
INSERT INTO t2 VALUES (0),(1);
EXPLAIN
SELECT MIN(a), b FROM t1 WHERE a > 0 GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL b 10 NULL 10 Using where; Using index for group-by
SELECT MIN(a), b FROM t1 WHERE a > 0 GROUP BY b;
MIN(a) b
1 0
9 99
EXPLAIN
SELECT MIN(a), b FROM t1 WHERE a > ( SELECT c FROM t2 WHERE c = 0 ) GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
2013-02-28 22:47:29 +01:00
1 PRIMARY t1 range NULL b 10 NULL 10 Using where; Using index for group-by
2013-02-13 11:58:16 +02:00
2 SUBQUERY t2 ALL NULL NULL NULL NULL 2 Using where
SELECT MIN(a), b FROM t1 WHERE a > ( SELECT c FROM t2 WHERE c = 0 ) GROUP BY b;
MIN(a) b
1 0
9 99
EXPLAIN
SELECT MIN(a), b FROM t1 WHERE a > ( SELECT min(c) FROM t2, t1 t1a, t1 t1b WHERE c = 0 ) GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL b 10 NULL 9 Using where; Using index
2 SUBQUERY t2 ALL NULL NULL NULL NULL 2 Using where
2 SUBQUERY t1a index NULL b 10 NULL 9 Using index; Using join buffer (flat, BNL join)
2 SUBQUERY t1b index NULL b 10 NULL 9 Using index; Using join buffer (incremental, BNL join)
SELECT MIN(a), b FROM t1 WHERE a > ( SELECT min(c) FROM t2, t1 t1a, t1 t1b WHERE c = 0 ) GROUP BY b;
MIN(a) b
1 0
9 99
drop table t1, t2;
2013-02-04 17:35:48 +02:00
End of 5.3 tests
2013-02-28 22:47:29 +01:00
#
2009-09-28 10:21:25 +03:00
# WL#3220 (Loose index scan for COUNT DISTINCT)
#
CREATE TABLE t1 (a INT, b INT, c INT, KEY (a,b));
INSERT INTO t1 VALUES (1,1,1), (1,2,1), (1,3,1), (1,4,1);
INSERT INTO t1 SELECT a, b + 4, 1 FROM t1;
INSERT INTO t1 SELECT a + 1, b, 1 FROM t1;
CREATE TABLE t2 (a INT, b INT, c INT, d INT, e INT, f INT, KEY (a,b,c));
INSERT INTO t2 VALUES (1,1,1,1,1,1), (1,2,1,1,1,1), (1,3,1,1,1,1),
(1,4,1,1,1,1);
INSERT INTO t2 SELECT a, b + 4, c,d,e,f FROM t2;
INSERT INTO t2 SELECT a + 1, b, c,d,e,f FROM t2;
EXPLAIN SELECT COUNT(DISTINCT a) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 5 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT a) FROM t1;
COUNT(DISTINCT a)
2
EXPLAIN SELECT COUNT(DISTINCT a,b) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 10 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT a,b) FROM t1;
COUNT(DISTINCT a,b)
16
EXPLAIN SELECT COUNT(DISTINCT b,a) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 10 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT b,a) FROM t1;
COUNT(DISTINCT b,a)
16
EXPLAIN SELECT COUNT(DISTINCT b) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 10 NULL 16 Using index
SELECT COUNT(DISTINCT b) FROM t1;
COUNT(DISTINCT b)
8
EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 5 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT a) FROM t1 GROUP BY a;
COUNT(DISTINCT a)
1
1
EXPLAIN SELECT COUNT(DISTINCT b) FROM t1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 10 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT b) FROM t1 GROUP BY a;
COUNT(DISTINCT b)
8
8
EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 10 NULL 16 Using index; Using filesort
SELECT COUNT(DISTINCT a) FROM t1 GROUP BY b;
COUNT(DISTINCT a)
2
2
2
2
2
2
2
2
EXPLAIN SELECT DISTINCT COUNT(DISTINCT a) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 10 NULL 16 Using index
SELECT DISTINCT COUNT(DISTINCT a) FROM t1;
COUNT(DISTINCT a)
2
EXPLAIN SELECT COUNT(DISTINCT a, b + 0) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 10 NULL 16 Using index
SELECT COUNT(DISTINCT a, b + 0) FROM t1;
COUNT(DISTINCT a, b + 0)
16
EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 HAVING COUNT(DISTINCT b) < 10;
id select_type table type possible_keys key key_len ref rows Extra
Bug#12328597 - MULTIPLE COUNT(DISTINCT) IN SAME SELECT FALSE
WITH COMPOSITE KEY COLUMNS
Problem:-
While running a SELECT query with several AGGR(DISTINCT) function
and these are referring to different field of same composite key,
Returned incorrect value.
Analysis:-
In a table, where we have composite key like (a,b,c)
and when we give a query like
select COUNT(DISTINCT b), SUM(DISTINCT a) from ....
here, we first make a list of items in Aggr(distinct) function
(which is a, b), where order of item doesn't matter.
and then we see, whether we have a composite key where the prefix
of index columns matches the items of the aggregation function.
(in this case we have a,b,c).
if yes, so we can use loose index scan and we need not perform
duplicate removal to distinct in our aggregate function.
In our table, we traverse column marked with <-- and get the result as
(a,b,c) count(distinct b) sum(distinct a)
treated as count b treated as sum(a)
(1,1,2)<-- 1 1
(1,2,2)<-- 1++=2 1+1=2
(1,2,3)
(2,1,2)<-- 2++=3 1+1+2=4
(2,2,2)<-- 3++=4 1+1+2+2=6
(2,2,3)
result will be 4,6, but it should be (2,3)
As in this case, our assumption is incorrect. If we have
query like
select count(distinct a,b), sum(distinct a,b)from ..
then we can use loose index scan
Solution:-
In our query, when we have more then one aggr(distinct) function
then they should refer to same fields like
select count(distinct a,b), sum(distinct a,b) from ..
-->we can use loose scan index as both aggr(distinct) refer to same fields a,b.
If they are referring to different field like
select count(distinct a), sum(distinct b) from ..
-->will not use loose scan index as both aggr(distinct) refer to different fields.
2013-05-13 17:15:25 +05:30
1 SIMPLE t1 index NULL a 10 NULL 16 Using index
2009-09-28 10:21:25 +03:00
SELECT COUNT(DISTINCT a) FROM t1 HAVING COUNT(DISTINCT b) < 10;
COUNT(DISTINCT a)
Bug#12328597 - MULTIPLE COUNT(DISTINCT) IN SAME SELECT FALSE
WITH COMPOSITE KEY COLUMNS
Problem:-
While running a SELECT query with several AGGR(DISTINCT) function
and these are referring to different field of same composite key,
Returned incorrect value.
Analysis:-
In a table, where we have composite key like (a,b,c)
and when we give a query like
select COUNT(DISTINCT b), SUM(DISTINCT a) from ....
here, we first make a list of items in Aggr(distinct) function
(which is a, b), where order of item doesn't matter.
and then we see, whether we have a composite key where the prefix
of index columns matches the items of the aggregation function.
(in this case we have a,b,c).
if yes, so we can use loose index scan and we need not perform
duplicate removal to distinct in our aggregate function.
In our table, we traverse column marked with <-- and get the result as
(a,b,c) count(distinct b) sum(distinct a)
treated as count b treated as sum(a)
(1,1,2)<-- 1 1
(1,2,2)<-- 1++=2 1+1=2
(1,2,3)
(2,1,2)<-- 2++=3 1+1+2=4
(2,2,2)<-- 3++=4 1+1+2+2=6
(2,2,3)
result will be 4,6, but it should be (2,3)
As in this case, our assumption is incorrect. If we have
query like
select count(distinct a,b), sum(distinct a,b)from ..
then we can use loose index scan
Solution:-
In our query, when we have more then one aggr(distinct) function
then they should refer to same fields like
select count(distinct a,b), sum(distinct a,b) from ..
-->we can use loose scan index as both aggr(distinct) refer to same fields a,b.
If they are referring to different field like
select count(distinct a), sum(distinct b) from ..
-->will not use loose scan index as both aggr(distinct) refer to different fields.
2013-05-13 17:15:25 +05:30
2
2009-09-28 10:21:25 +03:00
EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 HAVING COUNT(DISTINCT c) < 10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 16
SELECT COUNT(DISTINCT a) FROM t1 HAVING COUNT(DISTINCT c) < 10;
COUNT(DISTINCT a)
2
EXPLAIN SELECT 1 FROM t1 HAVING COUNT(DISTINCT a) < 10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 5 NULL 9 Using index for group-by
SELECT 1 FROM t1 HAVING COUNT(DISTINCT a) < 10;
1
1
EXPLAIN SELECT 1 FROM t1 GROUP BY a HAVING COUNT(DISTINCT b) > 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 10 NULL 9 Using index for group-by
SELECT 1 FROM t1 GROUP BY a HAVING COUNT(DISTINCT b) > 1;
1
1
1
EXPLAIN SELECT COUNT(DISTINCT t1_1.a) FROM t1 t1_1, t1 t1_2 GROUP BY t1_1.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1_1 index NULL a 10 NULL 16 Using index; Using temporary; Using filesort
2011-10-19 21:45:18 +02:00
1 SIMPLE t1_2 index NULL a 10 NULL 16 Using index; Using join buffer (flat, BNL join)
2009-09-28 10:21:25 +03:00
SELECT COUNT(DISTINCT t1_1.a) FROM t1 t1_1, t1 t1_2 GROUP BY t1_1.a;
COUNT(DISTINCT t1_1.a)
1
1
EXPLAIN SELECT COUNT(DISTINCT a), 12 FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 5 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT a), 12 FROM t1;
COUNT(DISTINCT a) 12
2 12
EXPLAIN SELECT COUNT(DISTINCT a, b, c) FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 15 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT a, b, c) FROM t2;
COUNT(DISTINCT a, b, c)
16
EXPLAIN SELECT COUNT(DISTINCT a), SUM(DISTINCT a), AVG(DISTINCT a) FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 5 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT a), SUM(DISTINCT a), AVG(DISTINCT a) FROM t2;
COUNT(DISTINCT a) SUM(DISTINCT a) AVG(DISTINCT a)
2 3 1.5000
EXPLAIN SELECT COUNT(DISTINCT a), SUM(DISTINCT a), AVG(DISTINCT f) FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 16
SELECT COUNT(DISTINCT a), SUM(DISTINCT a), AVG(DISTINCT f) FROM t2;
COUNT(DISTINCT a) SUM(DISTINCT a) AVG(DISTINCT f)
2 3 1.0000
EXPLAIN SELECT COUNT(DISTINCT a, b), COUNT(DISTINCT b, a) FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 10 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT a, b), COUNT(DISTINCT b, a) FROM t2;
COUNT(DISTINCT a, b) COUNT(DISTINCT b, a)
16 16
EXPLAIN SELECT COUNT(DISTINCT a, b), COUNT(DISTINCT b, f) FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 16
SELECT COUNT(DISTINCT a, b), COUNT(DISTINCT b, f) FROM t2;
COUNT(DISTINCT a, b) COUNT(DISTINCT b, f)
16 8
EXPLAIN SELECT COUNT(DISTINCT a, b), COUNT(DISTINCT b, d) FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 16
SELECT COUNT(DISTINCT a, b), COUNT(DISTINCT b, d) FROM t2;
COUNT(DISTINCT a, b) COUNT(DISTINCT b, d)
16 8
EXPLAIN SELECT a, c, COUNT(DISTINCT c, a, b) FROM t2 GROUP BY a, b, c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 15 NULL 9 Using index for group-by
SELECT a, c, COUNT(DISTINCT c, a, b) FROM t2 GROUP BY a, b, c;
a c COUNT(DISTINCT c, a, b)
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
2010-02-12 11:51:52 +03:00
1 1 1
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2 1 1
2 1 1
2 1 1
2 1 1
2 1 1
2 1 1
2 1 1
2 1 1
EXPLAIN SELECT COUNT(DISTINCT c, a, b) FROM t2
WHERE a > 5 AND b BETWEEN 10 AND 20 GROUP BY a, b, c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range a a 15 NULL 1 Using where; Using index for group-by
SELECT COUNT(DISTINCT c, a, b) FROM t2
WHERE a > 5 AND b BETWEEN 10 AND 20 GROUP BY a, b, c;
COUNT(DISTINCT c, a, b)
EXPLAIN SELECT COUNT(DISTINCT b), SUM(DISTINCT b) FROM t2 WHERE a = 5
GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref a a 5 const 1 Using where; Using index
SELECT COUNT(DISTINCT b), SUM(DISTINCT b) FROM t2 WHERE a = 5
GROUP BY b;
COUNT(DISTINCT b) SUM(DISTINCT b)
EXPLAIN SELECT a, COUNT(DISTINCT b), SUM(DISTINCT b) FROM t2 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 10 NULL 9 Using index for group-by
SELECT a, COUNT(DISTINCT b), SUM(DISTINCT b) FROM t2 GROUP BY a;
a COUNT(DISTINCT b) SUM(DISTINCT b)
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1 8 36
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2 8 36
EXPLAIN SELECT COUNT(DISTINCT b), SUM(DISTINCT b) FROM t2 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 10 NULL 9 Using index for group-by
SELECT COUNT(DISTINCT b), SUM(DISTINCT b) FROM t2 GROUP BY a;
COUNT(DISTINCT b) SUM(DISTINCT b)
8 36
8 36
EXPLAIN SELECT COUNT(DISTINCT a, b) FROM t2 WHERE c = 13 AND d = 42;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 16 Using where
SELECT COUNT(DISTINCT a, b) FROM t2 WHERE c = 13 AND d = 42;
COUNT(DISTINCT a, b)
0
EXPLAIN SELECT a, COUNT(DISTINCT a), SUM(DISTINCT a) FROM t2
WHERE b = 13 AND c = 42 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 15 NULL 9 Using where; Using index for group-by
SELECT a, COUNT(DISTINCT a), SUM(DISTINCT a) FROM t2
WHERE b = 13 AND c = 42 GROUP BY a;
a COUNT(DISTINCT a) SUM(DISTINCT a)
EXPLAIN SELECT COUNT(DISTINCT a, b), SUM(DISTINCT a) FROM t2 WHERE b = 42;
id select_type table type possible_keys key key_len ref rows Extra
Bug#12328597 - MULTIPLE COUNT(DISTINCT) IN SAME SELECT FALSE
WITH COMPOSITE KEY COLUMNS
Problem:-
While running a SELECT query with several AGGR(DISTINCT) function
and these are referring to different field of same composite key,
Returned incorrect value.
Analysis:-
In a table, where we have composite key like (a,b,c)
and when we give a query like
select COUNT(DISTINCT b), SUM(DISTINCT a) from ....
here, we first make a list of items in Aggr(distinct) function
(which is a, b), where order of item doesn't matter.
and then we see, whether we have a composite key where the prefix
of index columns matches the items of the aggregation function.
(in this case we have a,b,c).
if yes, so we can use loose index scan and we need not perform
duplicate removal to distinct in our aggregate function.
In our table, we traverse column marked with <-- and get the result as
(a,b,c) count(distinct b) sum(distinct a)
treated as count b treated as sum(a)
(1,1,2)<-- 1 1
(1,2,2)<-- 1++=2 1+1=2
(1,2,3)
(2,1,2)<-- 2++=3 1+1+2=4
(2,2,2)<-- 3++=4 1+1+2+2=6
(2,2,3)
result will be 4,6, but it should be (2,3)
As in this case, our assumption is incorrect. If we have
query like
select count(distinct a,b), sum(distinct a,b)from ..
then we can use loose index scan
Solution:-
In our query, when we have more then one aggr(distinct) function
then they should refer to same fields like
select count(distinct a,b), sum(distinct a,b) from ..
-->we can use loose scan index as both aggr(distinct) refer to same fields a,b.
If they are referring to different field like
select count(distinct a), sum(distinct b) from ..
-->will not use loose scan index as both aggr(distinct) refer to different fields.
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1 SIMPLE t2 index NULL a 15 NULL 16 Using where; Using index
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SELECT COUNT(DISTINCT a, b), SUM(DISTINCT a) FROM t2 WHERE b = 42;
COUNT(DISTINCT a, b) SUM(DISTINCT a)
0 NULL
EXPLAIN SELECT SUM(DISTINCT a), MAX(b) FROM t2 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 5 NULL 9 Using index for group-by
SELECT SUM(DISTINCT a), MAX(b) FROM t2 GROUP BY a;
SUM(DISTINCT a) MAX(b)
1 8
2 8
EXPLAIN SELECT 42 * (a + c + COUNT(DISTINCT c, a, b)) FROM t2 GROUP BY a, b, c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 15 NULL 9 Using index for group-by
SELECT 42 * (a + c + COUNT(DISTINCT c, a, b)) FROM t2 GROUP BY a, b, c;
42 * (a + c + COUNT(DISTINCT c, a, b))
126
126
126
126
126
126
126
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126
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168
168
168
168
168
168
168
168
EXPLAIN SELECT (SUM(DISTINCT a) + MAX(b)) FROM t2 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range NULL a 5 NULL 9 Using index for group-by
SELECT (SUM(DISTINCT a) + MAX(b)) FROM t2 GROUP BY a;
(SUM(DISTINCT a) + MAX(b))
9
10
DROP TABLE t1,t2;
# end of WL#3220 tests
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#
# Bug#50539: Wrong result when loose index scan is used for an aggregate
# function with distinct
#
CREATE TABLE t1 (
f1 int(11) NOT NULL DEFAULT '0',
f2 char(1) NOT NULL DEFAULT '',
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KEY (f1,f2)
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) ;
insert into t1 values(1,'A'),(1 , 'B'), (1, 'C'), (2, 'A'),
(3, 'A'), (3, 'B'), (3, 'C'), (3, 'D');
SELECT f1, COUNT(DISTINCT f2) FROM t1 GROUP BY f1;
f1 COUNT(DISTINCT f2)
1 3
2 1
3 4
explain SELECT f1, COUNT(DISTINCT f2) FROM t1 GROUP BY f1;
id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range NULL f1 5 NULL 9 Using index for group-by (scanning)
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drop table t1;
# End of test#50539.
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#
# MDEV-4219 A simple select query returns random data (upstream bug#68473)
#
drop table if exists faulty;
CREATE TABLE faulty (
a int(11) unsigned NOT NULL AUTO_INCREMENT,
b int(11) unsigned NOT NULL,
c datetime NOT NULL,
PRIMARY KEY (a),
UNIQUE KEY b_and_c (b,c)
);
INSERT INTO faulty (b, c) VALUES
(1801, '2013-02-15 09:00:00'),
(1802, '2013-02-28 09:00:00'),
(1802, '2013-03-01 09:00:00'),
(5, '1990-02-15 09:00:00'),
(5, '2013-02-15 09:00:00'),
(5, '2009-02-15 17:00:00');
EXPLAIN
SELECT DISTINCT b, c FROM faulty WHERE b='1802' ORDER BY c;
id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE faulty ref b_and_c b_and_c 4 const 2 Using where; Using index
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SELECT DISTINCT b, c FROM faulty WHERE b='1802' ORDER BY c;
b c
1802 2013-02-28 09:00:00
1802 2013-03-01 09:00:00
drop table faulty;
CREATE TABLE t1 (a INT, b INT);
INSERT INTO t1 (a, b) VALUES (1,1), (1,2), (1,3);
INSERT INTO t1 SELECT a + 1, b FROM t1;
INSERT INTO t1 SELECT a + 2, b FROM t1;
CREATE INDEX break_it ON t1 (a, b);
EXPLAIN
SELECT distinct a, b FROM t1 where a = '3' ORDER BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range break_it break_it 10 NULL 2 Using where; Using index for group-by; Using filesort
SELECT distinct a, b FROM t1 where a = '3' ORDER BY b;
a b
3 1
3 2
3 3
drop table t1;
