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

     )