select ROUND(AVG(TOTAL_VALUE)) AS SA_MEDIAN
from (
    select sub.TOTAL_VALUE
    from ( 
        select TOTAL_VALUE, ROW_NUMBER() OVER (ORDER BY TOTAL_VALUE) as row, COUNT(*) OVER () as total_rows
    from CONVENIENCE 
    where  SURVEY_YEAR = "2019" and KIND_CODE = "100") sub 
    inner join CONVENIENCE as c on sub.TOTAL_VALUE = c.TOTAL_VALUE
where sub.row in ((total_rows + 1) / 2,(total_rows + 2) / 2)
)