select
    USER_ID as USER, point as PT, round((point-a)*(case when d=0 then 0 else 10.0/d end)+50,1) as DEV_VAL
from TEST_RESULTS
inner join (
    select
        sqrt(sum((point - a)*(point - a))*1.0/c) as d
    from
        TEST_RESULTS
        inner join (
            select avg(POINT) as a
            from TEST_RESULTS
            where TEST_ID=100
        )
        inner join (
            select count(POINT) as c
            from TEST_RESULTS
            where TEST_ID=100
        )
    where test_id=100
) inner join (
    select avg(POINT) as a
    from TEST_RESULTS
    where TEST_ID=100
)
where test_id=100
order by DEV_VAL desc,USER_ID