笔记9 over开窗函数实现 cross apply的功能

笔记9 over开窗函数实现 cross apply的功能  

--over开窗函数实现 cross apply的功能  
declare @tb table([name] varchar(2),[group] varchar(2),[sales] int)
insert @tb
select 'aa','G1',3 union all
select 'bb','G1',5 union all
select 'cc','G2',4 union all
select 'dd','G2',3

--SELECT * FROM @tb
select name,[group] ,sales
from
(
select *,max([sales]) over(partition by [group] ) as max_sales_group from @tb
) as a
where a.[max_sales_group]=a.[sales]