select 
    USER_ID as 'USER',
    POINT as 'PT',
    CASE WHEN STDEV = 0 THEN 50
    ELSE round((POINT -  avg(POINT) OVER()) * 10 / STDEV + 50, 1) END 'DEV_VAL'
from (
select
    USER_ID,
    POINT,
    (select sqrt(avg(a)) from (
        select 
            POW((POINT -  avg(POINT) OVER()),2) as a
        from TEST_RESULTS
        where TEST_ID = 100
    )) as 'STDEV'
from TEST_RESULTS
where TEST_ID = 100
) order by 3 desc, 1