-- 1. Code 테이블을 만들어 관리하는 방법
WITH code_t AS
(
SELECT '등급표시불가' grd, 0 sp, 69 ep, Null amt FROM dual
UNION ALL SELECT 'A', 120, 999, 20000000 FROM dual
UNION ALL SELECT 'B',  90, 119, 10000000 FROM dual
UNION ALL SELECT 'C',  70,  89,  5000000 FROM dual
)
, data_t AS
(
SELECT 130 p FROM dual
UNION ALL SELECT 100 FROM dual
UNION ALL SELECT  80 FROM dual
UNION ALL SELECT  60 FROM dual
)
SELECT d.p, c.grd, c.amt
  FROM data_t d
     , code_t c
 WHERE d.p BETWEEN c.sp AND c.ep
;

-- 2. 그냥 Case 문으로 하는 방법
WITH data_t AS
(
SELECT 130 p FROM dual
UNION ALL SELECT 100 FROM dual
UNION ALL SELECT  80 FROM dual
UNION ALL SELECT  60 FROM dual
)
SELECT p
     , CASE WHEN p >= 120             THEN 'A'
            WHEN p >=  90 AND p < 120 THEN 'B'
            WHEN p >=  70 AND p <  90 THEN 'C'
            WHEN              p <  70 THEN '등급표시불가'
        END AS grd
     , CASE WHEN p >= 120             THEN 20000000
            WHEN p >=  90 AND p < 120 THEN 10000000
            WHEN p >=  70 AND p <  90 THEN  5000000
            WHEN              p <  70 THEN     null
        END AS amt
  FROM data_t
;