WITH AVG as (
 SELECT AVG(POINT) AS avg FROM TEST_RESULTS WHERE TEST_ID = '100'
), DIFF as (
 SELECT point - avg AS diff FROM TEST_RESULTS LEFT OUTER JOIN AVG WHERE TEST_ID = '100'
), VARIANCE as (
 SELECT AVG(POW(diff, 2)) as variance FROM DIFF
), SIGMA as(
 SELECT SQRT(variance) AS sigma FROM VARIANCE
)
 
SELECT
result.USER_ID AS USER,
result.POINT AS PT,
CASE
 WHEN SIGMA = 0 THEN 50
 ELSE ROUND((result.point - avg) * 10 / sigma + 50, 1) 
END AS DEV_VAL
FROM TEST_RESULTS result
LEFT OUTER JOIN AVG
LEFT OUTER JOIN SIGMA
WHERE TEST_ID = '100'
ORDER BY DEV_VAL DESC, result.USER_ID ASC;