查询表里重复记录并删除

select obj_id from ct_arch_mark group by obj_id having count(obj_id) > 1;

delete from ct_arch_mark
 where obj_id in (select obj_id
                      from ct_arch_mark
                     group by obj_id
                    having count(obj_id) > 1)
   and rowid not in (select min(rowid)
                       from ct_arch_mark
                      group by obj_id
                     having count(obj_id) > 1)