with k as(
    select count(total_value) as c
    from CONVENIENCE
    where SURVEY_YEAR=2019 and KIND_CODE=100
),
t as (
    select TOTAL_VALUE, rank() over(order by TOTAL_VALUE) as r, c
    from CONVENIENCE inner join k
    where SURVEY_YEAR=2019 and KIND_CODE=100
)
select round(avg(t.total_value)) as SA_MEDIAN
from t
where r=(c+1)/2 or r=(c+2)/2