group-by - where expression group by (col) vs group by (col) 有表达式

Question

样品表：

 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

他们返回相同的结果。在这里，我有一个疑问。那是：

哪个查询有效..？专家首选哪个查询？

将来，答案对我们非常有用。

谢谢，泰米尔语。

标签： group-bysql-server-2014havingssms-2012