-- @은 특수문자로 대체해주세요.. 못만들겠어요.. 샘플데이타가 더힘듬..
WITH T AS (
SELECT 1 FLD_KEY ,'123456A`234@5678@0530020' ACL_KEY_CODE FROM DUAL UNION ALL
SELECT 2,'1234562`2345678@0530021`0530022' FROM DUAL UNION ALL
SELECT 3,'1234563`23456@78`l' FROM DUAL UNION ALL
SELECT 4,'1234564`234@5678`c' FROM DUAL UNION ALL
SELECT 5,'1234565`23456@78`7' FROM DUAL 
)
SELECT * FROM 
 (SELECT FLD_KEY , REGEXP_SUBSTR(TXT,'[^`]+',1,LV) STR , lv FROM
   (SELECT FLD_KEY , REPLACE(ACL_KEY_CODE,chr(13)||chr(10),'`') txt FROM T )a , 
   (SELECT LEVEL lv FROM DUAL CONNECT BY LEVEL <= 10 ) b
 WHERE lv <= LENGTH(TXT) - LENGTH(REPLACE(TXT,'`',''))+1 )
WHERE LENGTH(STR) = 7 
 AND REGEXP_LIKE(STR,'^[[:digit:]]*$')
 ORDER BY FLD_KEY , lv
 

-- 숫자 8자리는 없다고 가정하면 간단하게...
SELECT fld_key
     , lv
     , REGEXP_SUBSTR(acl_key_code, '[0-9]{7}', 1, lv) v
  FROM t
     , (SELECT LEVEL lv FROM dual CONNECT BY LEVEL <= 99)
 WHERE lv <= REGEXP_COUNT(acl_key_code, '[0-9]{7}')
 ORDER BY fld_key, lv
;

SELECT fld_key
     , lv
     , REGEXP_SUBSTR(acl_key_code, '[0-9]{7}', 1, lv) v
  FROM t
     , (SELECT LEVEL lv FROM dual CONNECT BY LEVEL <= 99)
-- WHERE lv <= REGEXP_COUNT(acl_key_code, '[0-9]{7}')
 WHERE lv <= LENGTH(REGEXP_REPLACE(acl_key_code, '([0-9]{7})|.', '\1')) / 7
 ORDER BY fld_key, lv
;