with x as (
    SELECT
      ROW_NUMBER() OVER(ORDER BY TOTAL_VALUE) as r
     ,TOTAL_VALUE
    FROM
        CONVENIENCE
    WHERE
        KIND_CODE = '100'
    AND SURVEY_YEAR = '2019'
    ORDER BY TOTAL_VALUE ASC
),
c as (
    SELECT
        (count(r)/2) as c1
        ,(count(r)/2)+1 as c2
    FROM
        x
)

SELECT
    case
        when c1 % 2 == 0 then
            round(avg(TOTAL_VALUE),0)
        else
            min(TOTAL_VALUE)
    end as SA_MEDIAN
FROM
    x
inner join c on x.r = c.c1 or x.r = c.c2