ORACLE 去除重复记录

      delete from tbl_talbe
      where (col1,col2,col3) in
     (select col1,col2,col3
       from tbl_table
       group by col1,col2,col3
       having count(*)>1)
     and rowid not in
     (
        select max(rowid)
        from tbl_table
        group by col1,col2,col3
        having count(*) >1
     )