WITH A(a) AS (
    SELECT
        AVG(point)
    FROM
        TEST_RESULTS
    WHERE
        TEST_ID = '100'
    )
    , S(s) AS (
        SELECT
                SQRT(AVG(POW((POINT - a),2))) AS s
            FROM
                TEST_RESULTS,A
            WHERE
                TEST_ID = '100'
    )
    SELECT
            USER_ID AS USER
            , POINT AS PT
            
            , IIF(s=0,
                50,
                ROUND((POINT - a) * 10 / s + 50,1)) AS DEV_VAL
        FROM
            TEST_RESULTS,A, S
        WHERE
            TEST_ID = '100'
        ORDER BY
            DEV_VAL DESC
            , USER_ID