tablename中有主键id,字段zhiduanme1,zhiduanname2我想查询出表中所有zhiduanname1不重复的所有字段的记录:
写成如下为什么还是出现重复的记录?
select * from tabelname where zhiduname in (select distinct zhiduname from tablename)
写成如下为什么还是出现重复的记录?
select * from tabelname where zhiduname in (select distinct zhiduname from tablename)
inner join
(select min(id) as id from tablename group by zhiduanname1) T
on tablename.id=T.id