with t as
(
select null kor, 'A' us, null jp, '미국,일본' rgn from dual union all 
select 'A' kor, null us, 'A' jp, '한국,일본' rgn from dual union all 
select 'A' kor, null us, 'A' jp, '한국,미국,일본' rgn from dual
)
select *
  from t
 where nvl(decode(kor,'A','1')||decode(us,'A','2')||decode(jp,'A','3'),'*') !=
       nvl(decode(sign(instr(rgn,'한국')),1,'1')||decode(sign(instr(rgn,'미국')),1,'2')||decode(sign(instr(rgn,'일본')),1,'3'),'*')

WITH T  (KOR, USA, JPN, AREA) AS 
(   SELECT NULL, 'A', NULL, '미국,일본' FROM DUAL UNION ALL
    SELECT NULL, 'A', 'A',  '일본,미국' FROM DUAL UNION ALL
    SELECT 'A', NULL, 'A' , '한국,일본' FROM DUAL UNION ALL
    SELECT 'A', 'A', 'A' , '한국,일본' FROM DUAL UNION ALL
    SELECT 'A', 'A', 'A' , '한국,한국' FROM DUAL UNION ALL
    SELECT 'A', NULL, 'A' , '한국,미국,일본' FROM DUAL
)
SELECT *
  FROM T
 WHERE NOT(    NVL2(KOR, 1, 0) = REGEXP_COUNT(AREA, '한국')
           AND NVL2(USA, 1, 0) = REGEXP_COUNT(AREA, '미국')
           AND NVL2(JPN, 1, 0) = REGEXP_COUNT(AREA, '일본'));

요청사항에 나와있지 않는 경우의 수가 더 있습니다.

위 쿼리를 보시고 원하시는 데이터인지 확인해보세요.

WITH t AS
(
SELECT '' 한국, 'A' 미국, '' 일본, '미국,일본' 지역 FROM dual
UNION ALL SELECT 'A', '', 'A', '한국,일본' FROM dual
UNION ALL SELECT 'A', '', 'A', '한국,미국,일본' FROM dual
)
SELECT *
  FROM t
 WHERE NVL2(한국, 1, 0) != SIGN(INSTR(지역, '한국'))
    OR NVL2(미국, 1, 0) != SIGN(INSTR(지역, '미국'))
    OR NVL2(일본, 1, 0) != SIGN(INSTR(지역, '일본'))
;