WITH stats AS (
    SELECT
        AVG(POINT) AS avg,
        (SUM(POINT * POINT) - SUM(POINT) * SUM(POINT) / COUNT(*)) / COUNT(*) AS variance
    FROM
        TEST_RESULTS
    WHERE
        TEST_ID = '100'
),
deviation AS (
    SELECT
        TR.USER_ID,
        TR.POINT,
        CASE 
            WHEN SQRT(stats.variance) = 0 THEN 50.0
            ELSE ROUND((TR.POINT - stats.avg) * 10 / SQRT(stats.variance) + 50.0, 1)
        END AS DEV_VAL
    FROM 
        TEST_RESULTS TR, stats
    WHERE 
        TR.TEST_ID = '100'
)
SELECT
    USER_ID AS USER,
    POINT AS PT,
    DEV_VAL
FROM 
    deviation
ORDER BY 
    DEV_VAL DESC, USER;