DELETE FROM EMP AS a
WHERE EXISTS (
 SELECT EMP_CODE,EMP_LAST_NAME,EMP_FIRST_NAME
   FROM EMP_INVALID AS b
   WHERE a.EMP_CODE = b.EMP_CODE
     AND a.EMP_LAST_NAME = b.EMP_LAST_NAME
     AND a.EMP_FIRST_NAME = b.EMP_FIRST_NAME
     AND a.VALID_FLG = b.VALID_FLG
   )
   ;