with target AS(
	select * 
	from test_results
	where test_id = '100'
) ,
p AS (
select 	
	count(point) as point_count
	,avg(point) as point_avg
from
	target
),
dev as (
	select 
	sqrt((1.0 / p.point_count * sum(pow(target.point - p.point_avg, 2)))) as deviation
	, p.point_avg  as point_avg
	from target, p
)

select 
	 target.user_id  USER
	,target.point PT
	,CASE
		when dev.deviation = 0 then 50
		else ROUND( ( (point - dev.point_avg) * 10.0 ) / dev.deviation + 50, 1)
	END DEV_VAL
from target, dev
order by
	 DEV_VAL DESC
	,USER