with cr as (
select *
, rank() over (order by total_value) - 1 r
, count() over () t
from convenience where survey_year = 2019 and kind_code = 100 order by total_value
)
, cr2 as (
select total_value from cr
where r = (t - 1) / 2 or r =  (t / 2)
)
select ROUND(avg(total_value)) as SA_MEDIAN from cr2