DELETE FROM
    EMP
WHERE 
    EMP_CODE = (
                    SELECT
                        EMP_INVALID.EMP_CODE
                    FROM
                        EMP_INVALID
                    INNER JOIN
                        EMP
                      ON
                        EMP_INVALID.EMP_CODE = EMP.EMP_CODE
                    WHERE
                        EMP.VALID_FLG <> 1
                        );