with t as (
select 'ㄱ' id, 10 a, 20 b, 70 c, 50 d, 60 e from dual
)
select id
     , wm_concat(vl) vl
  from (
         select a.id
              , decode(b.rn, 1, a.a
                           , 2, a.b
                           , 3, a.c
                           , 4, a.d
                           , 5, a.e
                ) vl
           from t a
              , (
                  select level rn
                    from dual
                 connect by level <= 5
                ) b
          order by 2 desc
       )
 where rownum <= 2
 group by id