delete FROM mc_test t
where t.rowid <(select max(rowid) from mc_test t1
where t1.row_id=t.row_id)
and t.row_id in(
select t.row_id from mc_test t
group by t.row_id
having count(*) >= 2);
delete FROM mc_test t
where t.rowid <(select max(rowid) from mc_test t1
where t1.row_id=t.row_id)
and t.row_id in(
select t.row_id from mc_test t
group by t.row_id
having count(*) >= 2);