create table tb(a varchar(10) , b varchar(10) , c int) insert into tb values('A' , 'B' , 1) insert into tb values('A' , 'B' , 2) insert into tb values('A' , 'C' , 3) insert into tb values('A' , 'C' , 4) goselect a , b, sum(c) c from tb group by a , b /* a b c ---------- ---------- ----------- A B 3 A C 7(所影响的行数为 2 行) */select a , b, sum(c) c from tb group by b , a /* a b c ---------- ---------- ----------- A B 3 A C 7(所影响的行数为 2 行) */drop table tb
insert into tb values('A' , 'B' , 1)
insert into tb values('A' , 'B' , 2)
insert into tb values('A' , 'C' , 3)
insert into tb values('A' , 'C' , 4)
goselect a , b, sum(c) c from tb group by a , b
/*
a b c
---------- ---------- -----------
A B 3
A C 7(所影响的行数为 2 行)
*/select a , b, sum(c) c from tb group by b , a
/*
a b c
---------- ---------- -----------
A B 3
A C 7(所影响的行数为 2 行)
*/drop table tb