oracle_删除同一列的重复数据

<!--删除同一列的重复数据  rowid 在orcle中 数据的物理地址--->
delete from tbl_over_picture_alarm a
 where rowid not in (select min(b.rowid)
                       from tbl_over_picture_alarm b
                      where a.picture_url = b.picture_url )