[SQL]一组数据中Name列相同值的最大Je与最小je的差

declare @t table(name varchar(),qy varchar(),je int)
insert into @t
select '产品一','北京',
union all select '产品一','上海',
union all select '产品二','北京',
union all select '产品三','上海',
union all select '产品三','北京',
union all select '产品四','上海',
--select * from @t a where not exists  --这是取表中的NAME相同的最大值
--(
--    select  from @t where name=a.name and je>a.je
--)
--第一个答案：
SELECT NAME,QY,JE-ISNULL((SELECT JE FROM @T WHERE NAME=A.NAME AND QY<>A.QY),)
FROM @T A
WHERE JE=(SELECT MAX(JE) FROM @T WHERE NAME=A.NAME)
ORDER BY NAME
--第二个答案
Select
      Name,
      qy,
      je-(Select
                Case When Min(je)=A.je Then  Else Min(je) End
          From
                @t
          Where Name=A.Name Group By Name) As je
From
      @t A
Where Not Exists
     (Select  From @t Where Name=A.Name And je>A.je)