-- a, b, c 컬럼 중에서도 다른 값이 있다면 d컬럼처럼 나와야하는건가요?

--일단은
 
with t (A,B,C,D) as (
select 1,2,3,4 from dual union all
select 1,2,3,5 from dual union all 
select 1,2,3,6 from dual)
select a,b,c
     , Listagg(d, '/') Within Group (Order By rownum) d
from t
group by a,b,c
;

-- 참고 하세요

http://www.gurubee.net/article/55512