WITH target AS (
    SELECT
        *
    FROM
        CONVENIENCE
    WHERE
        SURVEY_YEAR = 2019
        AND KIND_CODE = '100'
),
target_count AS (
    SELECT count(*) AS count FROM target
)
SELECT
    round(avg(TOTAL_VALUE)) AS SA_MEDIAN
FROM
    (
        SELECT
            TOTAL_VALUE
        FROM
            target
        ORDER BY
            TOTAL_VALUE
        LIMIT
            (SELECT abs((count % 2) - 2) FROM target_count)
        OFFSET
            (SELECT count / 2 FROM target_count)
    )sub
;