with t as (
select
user_id,
point

from test_results
where test_id = '100'
),

m as (
select 
avg(point) as m
from t
),

v as (
select
sqrt(avg((point - m) * (point - m)) ) as v
from t, m
)

select 
user_id as USER,
point as PT,
(50 + round(10 * (point - m) / v, 1)) as DEV_VAL

from t, m, v

order by (50 + round((point - m) / v, 1)) desc, user_id