select round(avg(x)) as SA_MEDIAN
from (
    select SUM(TOTAL_VALUE) as x
    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
        )
)
;