with TARGET_DATA as (
    select
        *
    from TEST_RESULTS
    where TEST_ID='100'
), STAT(STD, AVG_POINT) as (
    select
        pow(sum(pow(POINT - AVG_POINT, 2)) / N, 0.5)
        , AVG_POINT
    from TARGET_DATA, (select avg(POINT) as AVG_POINT, count(*) as N from TARGET_DATA)
)
select
    USER_ID as USER
    , POINT as PT
    , case
        when STD > 0 then round(10 * (POINT - AVG_POINT) / STD + 50, 1)
        else 50
    end as DEV_VAL
from TARGET_DATA, STAT
order by DEV_VAL desc, USER asc
;