比如这条sql语句:
sc表是这样的:
s# c# g
1 1 100
1 2 50
1 3 55
2 1 100
2 2 77
2 3 55
3 1 66
3 2 78
3 3 99
3 4 77
3 5 89
4 2 55
4 1 22
4 3 69
4 5 57sql语句是:SELECT [s#] from sc where [s#]>1 GROUP BY [S#]我想问的是,执行where过滤的时候是不是先得到>1的所有行,再进行group by 分组,是吗?问题好像有点傻,得个确认
sc表是这样的:
s# c# g
1 1 100
1 2 50
1 3 55
2 1 100
2 2 77
2 3 55
3 1 66
3 2 78
3 3 99
3 4 77
3 5 89
4 2 55
4 1 22
4 3 69
4 5 57sql语句是:SELECT [s#] from sc where [s#]>1 GROUP BY [S#]我想问的是,执行where过滤的时候是不是先得到>1的所有行,再进行group by 分组,是吗?问题好像有点傻,得个确认
drop table tb
go
create table tb(id int identity(1,1), name varchar(20))
insert into tb(name)
select 'z' union all
select 'z' union all
select 'y' union all
select 'y' union all
select 'y' union all
select 'w' union all
select 'w' union all
select 'w' select name from tb where id>2 group by nameCtrl+ L 看执行计划!