Select dm, Min(mc) As mc from test Group By dm Order By dmOrSelect dm, Max(mc) As mc from test Group By dm Order By dm
delete A from t A inner join (select dm ,max(mc) as mc from t group by dm having count(*)>1) B on A.dm=B.dm and A.mc<>B.mc OR: delete A from t A inner join (select dm ,min(mc) as mc from t group by dm having count(*)>1) B on A.dm=B.dm and A.mc<>B.mc
dm,
Min(mc) As mc
from test
Group By dm
Order By dmOrSelect
dm,
Max(mc) As mc
from test
Group By dm
Order By dm
(select dm ,max(mc) as mc from t group by dm having count(*)>1) B
on A.dm=B.dm and A.mc<>B.mc
OR:
delete A from t A inner join
(select dm ,min(mc) as mc from t group by dm having count(*)>1) B
on A.dm=B.dm and A.mc<>B.mc