WITH DATA as (
        select 
            *
        from convenience
        where
           survey_year = 2019
        and kind_code = '100'
        ORDER BY total_value desc
        )

select
    case
        (
        select 
            count(*) as rowcnt
            from DATA
        ) % 2
    when 0 THEN
        (select 
            round(avg(total_value)) 
        from 
        (
            select 
                row_number() over win rownum,
                pf_code, total_value 
            from DATA
            WINDOW win AS (ORDER BY total_value desc)
        ) as tbl
        where 
            rownum IN
            (
            select 
                (count(*) / 2)
            from DATA
            UNION ALL
            select 
                (count(*) / 2) + 1
            from DATA
            )
        )
    when 1 THEN
        (select 
            round(avg(total_value)) 
        from 
        (
            select 
                row_number() over win rownum,
                pf_code, total_value 
            from DATA
            WINDOW win AS (ORDER BY total_value desc)
        ) as tbl
        where 
            rownum =
            (
            select 
                round(count(*) / 2)
            from DATA
            )
        )
    END as SA_MEDIAN