with AVERAGE AS
(
    SELECT
    平均,
    分散,
    pow(分散,0.5) AS 標準偏差
    FROM
    (
        SELECT
        平均,
        AVG(pow(POINT - 平均,2)) AS 分散
        FROM
        (
            SELECT
            POINT,
            AVG(POINT) AS 平均
            FROM
            TEST_RESULTS
            WHERE
            TEST_ID = '100' 
        )
    )
)

SELECT 
USER_ID AS USER,
POINT AS PT,
CASE
WHEN AVERAGE.標準偏差 <> 0 THEN ROUND((((POINT - 平均)*10)/AVERAGE.標準偏差),1) + 50
ELSE
50
END AS DEV_VAL 
FROM
TEST_RESULTS,AVERAGE
WHERE
TEST_RESULTS.TEST_ID = '100' 
ORDER BY DEV_VAL  DESC,USER_ID ASC