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
            (2 - ((SELECT count FROM target_count) % 2))    -- odd 1, even 2
        OFFSET
            (SELECT (count - 1) / 2 FROM target_count)
    )sub
;