with x as (
    SELECT
      ROW_NUMBER() OVER(ORDER BY TOTAL_VALUE) as r
     ,TOTAL_VALUE
    FROM
        CONVENIENCE
    WHERE
        KIND_CODE = '100'
    AND SURVEY_YEAR IN ('2019','2020')
    ORDER BY TOTAL_VALUE ASC
),
c as (
    SELECT
        cast(count(r)/2 as integer) as c1
        ,cast(count(r)/2 as integer)+1 as c2
    FROM
        x
)
SELECT
    case
        when c1 % 2 == 0 then
            round(avg(TOTAL_VALUE),0)
        else
            max(TOTAL_VALUE)
    end as SA_MEDIAN
FROM
    x
inner join c on x.r = c.c1 or x.r = c.c2