with log as (
    select
        count() OVER() as len,
        TOTAL_VALUE,
        ROW_NUMBER() OVER(order by TOTAL_VALUE desc) as rn,
        ROW_NUMBER() OVER(order by TOTAL_VALUE asc) as rev_rn
    from
        CONVENIENCE
    where
        SURVEY_YEAR = 2019
        and KIND_CODE = 100
)
select
    round(avg(TOTAL_VALUE)) as SA_MEDIAN
from
    log
where
    rn = cast(len / 2 as interger)+1
    or rev_rn = cast(len / 2 as interger)+1