WITH dtTbl (dt, vals ) AS (
    SELECT TO_CHAR( TO_DATE('202005', 'YYYYMM') + (LEVEL-1) , 'YYYY-MM-DD'), LEVEL FROM DUAL CONNECT BY LEVEL <= 21
), rtTbl (dt, rto ) AS (
    SELECT '2020-05-09', 120 FROM dual UNION ALL
    SELECT '2020-05-19', 200 FROM dual 
)
SELECT TBL.ddt rtDate , TBL.dvals rtValue
    , dvals * ( CASE WHEN ddt = rdt THEN NVL(LEAD(rt) OVER(ORDER BY ddt) , 1) ELSE rt END ) AS colc_Value
FROM (
    SELECT 
        dtTbl.dt as ddt , dtTbl.vals dvals, rtTbl.dt rdt
        , ROUND(EXP(SUM(LN( CASE WHEN rtTbl.rto IS NULL THEN 1 ELSE rtTbl.rto/100 END )) OVER (ORDER BY dtTbl.dt DESC)),2) rt
    FROM dtTbl 
    LEFT JOIN rtTbl ON dtTbl.dt = rtTbl.dt
    -- WHERE dttbl.dt BETWEEN '2020-05-07' AND '2020-05-12' -- 보정 1건
       WHERE dttbl.dt BETWEEN '2020-05-07' AND '2020-05-19' -- 보정 2건
    -- WHERE dtTbl.dt BETWEEN '2020-05-01' AND '2020-05-08' -- 보정 없음
) TBL
ORDER BY rtDate

WITH base_t AS
(
SELECT '2020-05-01' dt, 1 v FROM dual
UNION ALL SELECT '2020-05-02',  2 FROM dual
UNION ALL SELECT '2020-05-03',  3 FROM dual
UNION ALL SELECT '2020-05-04',  4 FROM dual
UNION ALL SELECT '2020-05-05',  5 FROM dual
UNION ALL SELECT '2020-05-06',  6 FROM dual
UNION ALL SELECT '2020-05-07',  7 FROM dual
UNION ALL SELECT '2020-05-08',  8 FROM dual
UNION ALL SELECT '2020-05-09',  9 FROM dual
UNION ALL SELECT '2020-05-10', 10 FROM dual
UNION ALL SELECT '2020-05-11', 11 FROM dual
UNION ALL SELECT '2020-05-12', 12 FROM dual
UNION ALL SELECT '2020-05-13', 13 FROM dual
UNION ALL SELECT '2020-05-14', 14 FROM dual
UNION ALL SELECT '2020-05-15', 15 FROM dual
UNION ALL SELECT '2020-05-16', 16 FROM dual
UNION ALL SELECT '2020-05-17', 17 FROM dual
UNION ALL SELECT '2020-05-18', 18 FROM dual
UNION ALL SELECT '2020-05-19', 19 FROM dual
UNION ALL SELECT '2020-05-20', 20 FROM dual
UNION ALL SELECT '2020-05-21', 21 FROM dual
)
, rat_t AS
(
SELECT '2020-05-09' dt, 120 r FROM dual
UNION ALL SELECT '2020-05-19', 200 FROM dual
)
SELECT a.dt
     , a.v
     , b.r
     , a.v
     * NVL(ROUND(EXP(
       SUM(LN(b.r/100)) OVER(ORDER BY a.dt
       ROWS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING)
       ), 3), 1) x
  FROM base_t a
     , rat_t b
 WHERE a.dt = b.dt(+)
   AND a.dt BETWEEN '2020-05-07' AND '2020-05-19'
;

와우 이게 되는군요!! 두 분다 핵심적으로 쓰는 구문은 같네요. 고수분들은 역시 다르군요. 눈빠지게 들여다보고 공부하겠습니다.

감사합니다.