-- DELETE FROM TEST_RESULTS WHERE TEST_ID <> '100';
WITH SUB AS (
    SELECT SQRT(AVG(D)) AS S
    FROM (
        SELECT (POINT - (SELECT AVG(POINT) FROM TEST_RESULTS WHERE TEST_ID = '100')) * (POINT - (SELECT AVG(POINT) FROM TEST_RESULTS WHERE TEST_ID = '100'))  AS D
        FROM TEST_RESULTS
        WHERE TEST_ID = '100'
    )
)
SELECT USER_ID AS USER, POINT AS PT, CASE WHEN S = 0 THEN 50 ELSE ROUND((POINT - (SELECT AVG(POINT) FROM TEST_RESULTS WHERE TEST_ID = '100')) * 10 / S + 50, 1) END AS DEV_VAL
FROM TEST_RESULTS CROSS JOIN SUB
WHERE TEST_ID = '100'
ORDER BY DEV_VAL DESC, USER;