select
    USER_ID POINT,
    case
        when hyoujyunhensa <> 0 then ROUND(
            (
                POINT - (
                    SELECT
                        AVG(POINT)
                    FROM
                        TEST_RESULTS
                    where
                        TEST_ID = '100'
                )
            ) * 10 / hyoujyunhensa + 50,
            1
        )
        else 50.0
    end as DEV_VAL
from
    TEST_RESULTS
    inner join(
        select
            sqrt(AVG(POWER)) as hyoujyunhensa
        from
            (
                select
                    POWER(
                        POINT - (
                            SELECT
                                AVG(POINT)
                            FROM
                                TEST_RESULTS
                        ),
                        2
                    ) as POWER
                from
                    TEST_RESULTS
                where
                    TEST_ID = '100'
            )
    ) as hyoujyunhensa
where
    TEST_ID = '100'
order by
    DEV_VAL desc,
    USER_ID