1 查看一列重复行SQL语句
select khname
from mt_kh
where khname in
(select khname from mt_kh group by khname having count(khname) > 1)
2 查看多列重复行
select mtname,khname
from mt_kh
where (mtname, khname) in
(select mtname, khname from mt_kh group by mtname,khname having count(*) > 1)