delete from convenience where total_value = 0;

with cnt as (
    select
        count(1) cnt
    from
        CONVENIENCE c
    where
        c.KIND_CODE = '100'
        and c.SURVEY_YEAR = 2019
)
select
    cast(
        round(
            cast(sum(sub.TOTAL_VALUE) as real) / count(1)
        ) as INTEGER
    ) as "SA_MEDIAN"
from
    (
        select
            c.TOTAL_VALUE,
            row_number() over (
                order by
                    c.TOTAL_VALUE
            ) as rowid
        from
            CONVENIENCE c
        where
            c.KIND_CODE = '100'
            and c.SURVEY_YEAR = 2019
    ) sub
    join cnt
where
    (
        cnt.cnt % 2 = 1
        and sub.rowid = cnt.cnt / 2 + 1
    )
    or (
        cnt.cnt % 2 = 0
        and (
            sub.rowid = cnt.cnt / 2
            or sub.rowid = cnt.cnt / 2 - 1
        )
    );