WITH t AS
(
SELECT 'aaa' cd, 100 v FROM dual
UNION ALL SELECT 'bbb', 99 FROM dual
UNION ALL SELECT 'ccc', 98 FROM dual
UNION ALL SELECT 'ddd', 97 FROM dual
UNION ALL SELECT 'eee', 96 FROM dual
UNION ALL SELECT 'fff', 84 FROM dual
UNION ALL SELECT 'ggg', 70 FROM dual
UNION ALL SELECT 'hhh', 69 FROM dual
UNION ALL SELECT 'iii', 68 FROM dual
UNION ALL SELECT 'jjj', 50 FROM dual
UNION ALL SELECT 'kkk', 47 FROM dual
UNION ALL SELECT 'lll', 30 FROM dual
UNION ALL SELECT 'mmm', 28 FROM dual
)
SELECT MIN(DECODE(rn2, 1, cd)) grp1
     , MIN(DECODE(rn2, 2, cd)) grp2
     , MIN(DECODE(rn2, 3, cd)) grp3
     , MIN(DECODE(rn2, 4, cd)) grp4
     , MIN(DECODE(rn2, 5, cd)) grp5
  FROM (
        SELECT cd, v
             , rn
             , CEIL(rn / :grp) gb
             , ROW_NUMBER() OVER(
               PARTITION BY CEIL(rn / :grp)
               ORDER BY DECODE(MOD(CEIL(rn / :grp), 2), 0, v, -v)
               ) rn2
          FROM (
                SELECT cd, v
                     , ROW_NUMBER() OVER(ORDER BY v DESC) rn
                  FROM t
                )
        )
 GROUP BY gb
 ORDER BY gb
;

역시 마농님께서 답을 주셨네요. ^^*

항상 느끼지만 대단하세요.

export / Import 시 테이블 크기순으로 병렬작업으로 돌리려다 보니,

테이블을 비슷한 크기의 그룹으로 나누려고 문의 드렸던 건데요.

유용하게 사용할 것 같습니다.

오늘도 많이 배우고 갑니다.,