样本表:
create table #dev (name varchar(20), team varchar(10), qualification varchar(10))
insert into #dev values
('a','t','be')
,('b','d','bsc')
,('c','p','be')
,('d','j','be')
,('e','d','bsc')
,('f','j','bsc')
,('g','d','be')
,('h','j','be')
,('i','d','bsc')
,('j','j','bsc')
,('k','d','be')
select team,qualification,COUNT(qualification ) from #dev
group by team,qualification having qualification = 'be'
select team,qualification,COUNT(qualification ) from #dev
where qualification = 'be'
group by team,qualification
它们返回相同的结果。在这里,我有一个疑问。即:
哪个查询有效..? 专家首选哪种查询?
答案对我们将来会非常有用。
谢谢, 泰米尔语(TamilPugal)。