select round(avg(sum(TOTAL_VALUE))) as SA_MEDIAN
from (
    select SUM(TOTAL_VALUE)
    from CONVENIENCE
    where SURVEY_YEAR = 2019
    and KIND_CODE = 100
    
    group by PF_CODE
    
    order by TOTAL_VALUE
    limit 2 -(
        select count(*)
        from CONVENIENCE) % 2
    offset (
        select (count(*) - 1) / 2
        from CONVENIENCE
    )
)
;