如何用SQL排除重复结果只取字段最大值的记录？
要求得到的结果（即是PID相同的记录只取ID值最大的那一条）。
复制代码代码如下:
select * from [Sheet1$] a
where ID not exists (select 1 from [Sheet1$] where PID=a.PID and ID>a.ID)
select a.* from [Sheet1$] a inner join (select PID,max(ID) as max_id from [Sheet1$] group by PID) b on a.PID=b.PID and a.ID=b.max_id
