WITH TMP(USER_ID, POINT) AS (
    SELECT USER_ID, POINT
    FROM TEST_RESULTS
    WHERE TEST_ID = '100'
),
X_ AS (SELECT AVG(POINT) FROM TMP),
STDEV AS (
    SELECT SQRT(AVG(POWER(POINT - (SELECT * FROM X_), 2)))
    FROM TMP
)
SELECT USER, PT, ROUND(DEV, 1) DEV_VAL
FROM (
    SELECT USER_ID USER, POINT PT, (POINT - (SELECT * FROM X_)) * 10 / (SELECT * FROM STDEV) + 50 DEV
    FROM TMP
    ORDER BY DEV DESC, USER_ID ASC
)