WITH t AS
(
SELECT 12345 id, '숫자' v FROM dual
UNION ALL SELECT 67890, '숫자,문자' FROM dual
)
SELECT id, v
     , DECODE(v, '숫자', 'Y', 'N') yn
  FROM t
;

마농님 답변 감사합니다 근데 질문을 잘못 작성해서 수정했습니다.... 시간이 되신다면 다시 봐주시면 감사하겠습니다.....

WITH
    T AS
        (SELECT 12 ID, '숫자' V FROM DUAL
         UNION ALL
         SELECT 12, '숫자,숫자' FROM DUAL
         UNION ALL
         SELECT 12, '숫자,문자' FROM DUAL)
SELECT ID
     , V
     , DECODE(REGEXP_REPLACE(V, '^(숫자|,)+$', 'Y'), 'Y', 'Y', 'N') YN
  FROM T;

WITH T AS
(
SELECT 12 ID, '숫자' V FROM DUAL
UNION ALL
SELECT 12, '숫자,숫자' FROM DUAL
UNION ALL
SELECT 12, '숫자,문자' FROM DUAL
)
SELECT ID
, V
, CASE WHEN REGEXP_COUNT(V,'숫자') = REGEXP_COUNT(V,',') + 1 THEN 'Y' ELSE 'N' END CHK
FROM T;

WITH t AS
(
SELECT 12 no, '숫자' content     FROM dual
UNION ALL SELECT 12, '숫자,숫자' FROM dual
UNION ALL SELECT 13, '숫자'      FROM dual
UNION ALL SELECT 13, '숫자,문자' FROM dual
)
SELECT no
     , CASE WHEN SUM(INSTR(content, '숫자')) > 0
             AND SUM(INSTR(content, '문자')) = 0
       THEN 'Y' ELSE 'N' END yn
  FROM t
 GROUP BY no
 ORDER BY no
;