WITH summary1 AS (
    SELECT
        AVG(POINT)   as a
      , COUNT(POINT) as c
    FROM
        TEST_RESULTS
    WHERE
        TEST_ID = '100'
), summary2 AS (
    SELECT
        a
      , c
      , SQRT(
          SUM((POINT-a) * (POINT-a)) / (COUNT(POINT))
        ) as d
    FROM
        TEST_RESULTS
      , summary1
    WHERE
        TEST_ID = '100'
)
SELECT
    USER_ID as USER
  , POINT   as PT
  , CASE
       WHEN d = 0 THEN 50
       ELSE
           round((50 + (POINT - a) * 10 / d), 1)
    END
    as DEV_VAL
FROM
    TEST_RESULTS t
  , summary2     s
WHERE
    TEST_ID = '100'
ORDER BY
    DEV_VAL desc
  , USER    asc
;