delete from where rowid not in (
select min(rowid) from
group by );

delete from emp a where rowid >
any (select rowid from emp b where a.empid=b.empid);

delete from T t1 where t1.rowid >( select min(t2.rowID) from T t2
where t1.col1 = t2.col1 and t1.col2 = t2.col2);