比如我資料表如下:
userid username class
0001 lily 1
0002 lucy 1
0003 jim 2
0004 tom 3
0005 rose 3
0006 robet 4
如何把class列有重復的數據行查詢出來
也就是要查詢結果如下:
userid username class
0001 lily 1
0002 lucy 1
0004 tom 3
0005 rose 3
請幫忙,謝謝各位!
userid username class
0001 lily 1
0002 lucy 1
0003 jim 2
0004 tom 3
0005 rose 3
0006 robet 4
如何把class列有重復的數據行查詢出來
也就是要查詢結果如下:
userid username class
0001 lily 1
0002 lucy 1
0004 tom 3
0005 rose 3
請幫忙,謝謝各位!
where exists (
select 1 from tablename
where class=a.class
and userid<>a.userid
)
where class in
(
select class from tablename
group by class
having count(*)>1
)
where exists(select 1 from table where class = a.class group by class having count(*) > 1)