with avg as(
    select
        avg(POINT) as avg_point
    from
        TEST_RESULTS
    where
        TEST_ID = "100"
),
sd as(
    select
        abs(power(avg(power((t.POINT - avg.avg_point),2)),0.5))  as sd
    from
        TEST_RESULTS as t
    join
        avg 
    where
        TEST_ID = "100" 
)

select
    USER_ID as USER,
    POINT as PT,
    case sd.sd
    when 0 then 50
    else 50 + round(((t.POINT - avg.avg_point) * 10 / sd.sd),1) end as DEV_VAL 
from
    TEST_RESULTS as t
join
    sd
join
    avg
where
    TEST_ID = "100" 
order by
    DEV_VAL desc,
    USER