with TARGET as
(select
		USER_ID as USER, POINT as PT
	from
		TEST_RESULTS
	where
		TEST_ID = '100'
)
, step1 as
(select
		avg(PT) as AVG_POINT
	from
		TARGET
)
, step2_3 as
(select
		avg((PT-AVG_POINT) * (PT-AVG_POINT)) as BUNSAN
	from
		TARGET
	    cross join step1
)
select
	USER, PT,
	case
		when sqrt(BUNSAN) = 0 then 50.0
		else round((PT - AVG_POINT) * 10.0 / sqrt(BUNSAN) + 50.0, 1)
	end as DEV_VAL
from
	TARGET
	cross join step1
	cross join step2_3
order by
	DEV_VAL desc, USER