With

기본 형식

WITH tmp_table_name AS (
  SELECT * FROM (
    SELECT 'M1'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M2'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M3'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M4'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M5'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M6'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M7'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M8'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M9'  AS MCODE FROM DUAL UNION ALL
    SELECT 'M10' AS MCODE FROM DUAL UNION ALL
    SELECT 'M11' AS MCODE FROM DUAL UNION ALL
    SELECT 'M12' AS MCODE FROM DUAL
  )
)
SELECT * FROM tmp_table_name;

• 서브 쿼리 영역에 이름을 지정할 수 있게함
• 옵티마이저는 인라인뷰나 임시 테이블로 해석