ROW_NUM()函数的一个应用和查找到此表中按pingm分组中num值最大的那个

SELECT pingm, mid, num FROM dbo.TableUser WHERE num IN(SELECT MAX(dbo.TableUser.num) num FROM dbo.TableUser WHERE pingm IN (SELECT DISTINCT(pingm) FROM dbo.TableUser) GROUP BY dbo.TableUser.pingm)

  select pingm, mid, num from (
   select ROW_NUMBER () OVER ( PARTITION BY pingm ORDER BY num desc ) AS idx,pingm,mid ,num from TableUser 
   ) as a
   where idx = 1

查找到此表中按pingm分组中num值最大的那个

最下面的是一个qq网名为小付的网友写的，学习了