WITH AV AS (
    SELECT
        AVG(POINT) AS AVERAGE
    FROM
        TEST_RESULTS
    WHERE
        TEST_ID = '100'
)
SELECT
    USER_ID AS USER,
    POINT AS PT,
    CASE STANDARD_DEVIATION
    WHEN 0 THEN 50
    ELSE ROUND((POINT - AVERAGE) * 10 / STANDARD_DEVIATION + 50, 1)
    END AS DEV_VAL
FROM
    TEST_RESULTS
CROSS JOIN
    AV
CROSS JOIN (
    SELECT
        SQRT(AVG(POW(POINT - AVERAGE, 2))) AS STANDARD_DEVIATION
    FROM
        TEST_RESULTS
    CROSS JOIN
        AV
) AS
    SD
ORDER BY
    DEV_VAL DESC,
    USER_ID ASC