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 1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by 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 1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 # NULL # Using index for group-by 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 1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by 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 1 SIMPLE t1 range NULL idx_t1_1 130 NULL 5 Using index for group-by 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 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' 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 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 t2 where a1 < 'd' group by a1,a2,b; id select_type table type possible_keys key key_len ref rows Extra 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 1 SIMPLE t1 range NULL idx_t1_1 147 NULL # Using where; Using index for group-by 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 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 > 'b1') or (c <= 'g1') 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 > '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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 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 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 1 PRIMARY t1 range NULL idx_t1_1 147 NULL 17 Using index for group-by 2 SUBQUERY t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index 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 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 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 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 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 1 SIMPLE t2 range NULL idx_t2_1 163 NULL # Using where; Using index for group-by 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 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 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 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 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 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 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 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 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 index NULL idx_t2_1 163 NULL # Using where; Using index 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 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 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 a b a i121 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 explain 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 Extra 1 SIMPLE t1 index NULL idx_t1_1 163 NULL 128 Using where; Using index 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by explain 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 Extra 1 SIMPLE t2 index NULL idx_t2_1 163 NULL 164 Using where; Using index 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 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 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 select distinct t_00.a1 from t1 t_00 where exists ( select * from t2 where a1 = t_00.a1 ); a1 a b c d 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 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using index for group-by 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by 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 1 SIMPLE t2 index NULL idx_t2_1 163 NULL # Using where; Using index 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 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 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 1 SIMPLE t2 range NULL idx_t2_1 146 NULL # Using where; Using index for group-by; Using temporary; Using filesort 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 a b a i121 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 1 SIMPLE t1 index NULL idx_t1_2 147 NULL 128 Using where; Using index 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 1 SIMPLE t1 index NULL idx_t1_1 163 NULL 128 Using where; Using index explain 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 Extra 1 SIMPLE t1 index idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_2 147 NULL 128 Using where; Using index 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 explain select ord(a1) + count(distinct a1,a2,b) from t1 where (a1 > 'a') and (a2 > 'a'); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_2 147 NULL 128 Using where; Using index 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 select ord(a1) + count(distinct a1,a2,b) from t1 where (a1 > 'a') and (a2 > 'a'); ord(a1) + count(distinct a1,a2,b) 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 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 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 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 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 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 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 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 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 1 SIMPLE t1 range NULL idx_t1_1 147 NULL 9 Using index for group-by 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 explain select a1,a2,min(b),max(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; 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_1 130 NULL 76 Using where; Using index 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') and (d > 'xy2') group by a1,a2,b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL idx_t1_0,idx_t1_1,idx_t1_2 NULL NULL NULL 128 Using where; Using temporary; Using filesort explain select a1,a2,b,c from t1 where (a1 = 'b' or a1 = 'd' or a1 = 'a' or a1 = 'c') and (a2 > 'a') and (d > 'xy2') group by a1,a2,b,c; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL idx_t1_0,idx_t1_1,idx_t1_2 NULL NULL NULL 128 Using where; Using temporary; Using filesort 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 explain 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 Extra 1 SIMPLE t1 range idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 130 NULL 76 Using where; Using index 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 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 1 SIMPLE t1 index NULL idx_t1_1 163 NULL 128 Using index explain 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 Extra 1 SIMPLE t1 index idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 163 NULL 128 Using where; Using index explain 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 Extra 1 SIMPLE t1 index idx_t1_0,idx_t1_1,idx_t1_2 idx_t1_1 163 NULL 128 Using where; Using index explain select distinct(a1) from t1 where ord(a2) = 98; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL idx_t1_1 163 NULL 128 Using where; Using index select distinct(a1) from t1 where ord(a2) = 98; a1 a b c d 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 drop table t1,t2,t3; 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; 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; 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; CREATE TABLE t1 (a varchar(64) NOT NULL default '', PRIMARY KEY(a)); 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 1 SIMPLE t1 range NULL PRIMARY 66 NULL 12 Using index for group-by 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; 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; CREATE TABLE t1 (a int, b int, PRIMARY KEY (a,b), KEY b (b)); INSERT INTO t1 VALUES (1,1),(1,2),(1,0),(1,3); 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 1 SIMPLE t1 range PRIMARY,b PRIMARY 8 NULL 1 Using where; Using index for group-by 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 1 SIMPLE t2 range PRIMARY PRIMARY 12 NULL 1 Using where; Using index for group-by SELECT MIN(c) FROM t2 WHERE b = 2 and a = 1 and c > 1 GROUP BY a; MIN(c) 2 DROP TABLE t1,t2; 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 2 SUBQUERY t1 index NULL a 10 NULL 8 Using index 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 1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE 2 SUBQUERY t1 range NULL a 5 NULL 8 Using index for group-by 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 1 PRIMARY t1_outer index NULL a 10 NULL 15 Using where; Using index 2 DEPENDENT SUBQUERY t1 index NULL a 10 NULL 8 Using index 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 1 PRIMARY t1_outer1 ref a a 5 const 1 Using where; Using index 1 PRIMARY t1_outer2 index NULL a 10 NULL 15 Using where; Using index 2 SUBQUERY t1 range NULL a 5 NULL 8 Using index for group-by 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; Warnings: Error 1242 Subquery returns more than 1 row SHOW STATUS LIKE 'handler_read__e%'; Variable_name Value Handler_read_key 8 Handler_read_next 1 DROP TABLE t1,t2,t3; 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; 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; create table t1 (a int, b int, primary key (a,b), key `index` (a,b)) engine=MyISAM; 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); 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 explain extended select sql_buffer_result a, max(b)+1 from t1 where a = 0 group by a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range PRIMARY,index PRIMARY 4 NULL 6 Using where; Using index for group-by; Using temporary 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;