WITH tbl1 AS
(
SELECT 1 no, 'A' name FROM dual
UNION ALL SELECT 2, 'A' FROM dual
UNION ALL SELECT 2, 'B' FROM dual
UNION ALL SELECT 3, 'C' FROM dual
UNION ALL SELECT 4, 'D' FROM dual
UNION ALL SELECT 5, 'E' FROM dual
)
SELECT DISTINCT no FROM tbl1
UNION
SELECT DISTINCT name FROM tbl1;

위의 쿼리에서 TBL1 을 한번만 읽어서 처리하고 싶습니다.

감사합니다.