with t_y as (
    select user_id, point, point - (select avg(point) from TEST_RESULTS where test_id = '100') as diff
    from TEST_RESULTS
    where test_id = '100'
),
t_n as (
    select sqrt(sum(diff * diff) / count(*)) as nor
    from t_y
)

select user_id as USER, point as PT,
case
    WHEN (select nor from t_n) = 0 THEN 50
    ELSE round( diff * 10 / (select nor from t_n) + 50, 1)
end as DEV_VAL
from t_y
order by DEV_VAL desc, user_id