ORACLE ROLLUP 시 정렬 문제

원본 출처 : http://www.gurubee.net/article/54382

WITH T AS ( 
    SELECT 'A' COL1, 6 COL2, 40 COL3 FROM DUAL UNION ALL 
    SELECT 'A'     , 6     , 20      FROM DUAL UNION ALL 
    SELECT 'B'     , 1     , 2       FROM DUAL UNION ALL 
    SELECT 'B'     , 1     , 2       FROM DUAL 
) 
SELECT DECODE(1 
     , GROUPING(COL1), '총합계' 
     , GROUPING(ROWNUM), COL1 || '중간합계' 
     , COL1) COL
     , COL1
     , SUM(COL2) COL2 
     , SUM(COL3) COL3 
FROM   T 
GROUP  BY ROLLUP(COL1, ROWNUM) 
ORDER  BY GROUPING(T.COL1) DESC -- 총합계를 위로 
, COL1
, GROUPING(ROWNUM) -- 중간합계를 아래로 
, ROWNUM 
;