删除一张表中的重复数据

删除一张表中的重复数据  
delete /*+ nologging */  
           (select /*+ leading(d) use_hash(l, d) */
                   e.*
              from mid_cable_line_ex e,
                   (select ROWID,
                           ROW_NUMBER() over (PARTITION BY e.cable_code, e.line_no
                                                  ORDER BY e.cable_code, e.line_no)  rn
                      from mid_cable_line_ex e) mcle
              where e.rowid = mcle.rowid);