[oracle] ROWNUM이용해서 빈행 만들기

select 	decode(rownum, 1, a.val, 2, b.val, 3, c.val) 
from 	(select 'A' as val from dual) a
	, (select 'B' as val from dual) b
	, (select 'C' as val from dual) c 
	, (select rownum from dual connect by rownum <= 10)