강좌 참고해서 만들어봤습니다~

http://www.gurubee.net/article/55635

with t as (
select '20201005' 시작일, '20201007' 종료일, 'A' 구분 from dual
union all select '20201120', '20201122', 'B' from dual
)
select *
from (
select 시작일 + lv - 1 일자, 구분
from t, (select level lv from dual connect by level <= 30)
where lv <= 종료일 - 시작일 + 1
)
order by 일자, 구분

WITH t AS
(
SELECT '20201005' sdt, '20201007' edt, 'A' gb FROM dual
UNION ALL SELECT '20201120', '20201122', 'B'  FROM dual
UNION ALL SELECT '20201031', '20201101', 'C'  FROM dual
)
SELECT gb
     , TO_CHAR(s + lv - 1, 'yyyymmdd') dt
  FROM (SELECT gb
             , TO_DATE(sdt, 'yyyymmdd') s
             , TO_DATE(edt, 'yyyymmdd') e
          FROM t
        ) a
     , (SELECT LEVEL lv FROM dual CONNECT BY LEVEL <= 99) b
 WHERE lv <= e - s + 1
 ORDER BY gb, dt
;

지적 감사합니다~ 결과에만 급급했군요 ㅜ.ㅜ

마농님 pajama님 답변 감사합니다 :)