分组取头名的问题,解决方法如下,自己领会吧:
--"找到sxrq靠前三的商品,是每个spid的前三名",不知道sxrq的前三是按從小到大的順序還是從大到小的順序
--從小到大的順序
--方法一:
Select * From sphwph A Where (Select Count(*) From sphwph Where spid=A.spid And sxrq<A.sxrq)<3
--方法二:
Select * From sphwph A Where Not Exists(Select * from sphwph Where spid=A.spid And sxrq<A.sxrq Having Count(*)>2)
--方法三:
Select * From sphwph A Where sxrq In(Select Top 3 sxrq From sphwph Where spid=A.spid Order By sxrq)