delete a from kol_contacts a,
(select c.kol_id,c.mobile ,max(c.id) as bid from
kol_contacts c GROUP BY kol_id,mobile having count(*) >1
) b
where a.kol_id=b.kol_id and a.mobile = b.mobile and a.id < b.bid;
(select c.kol_id,c.mobile ,max(c.id) as bid from
kol_contacts c GROUP BY kol_id,mobile having count(*) >1
) b
where a.kol_id=b.kol_id and a.mobile = b.mobile and a.id < b.bid;