SELECT
    ROUND(AVG(TOTAL_VALUE), 0) AS SA_MEDIAN
FROM (
    SELECT
        ROW_NUMBER() OVER (ORDER BY TOTAL_VALUE) AS ROW,
        TOTAL_VALUE,
        COUNT() OVER () AS CNT
    FROM
        CONVENIENCE
    WHERE
        SURVEY_YEAR = 2019
        AND KIND_CODE = '100'
)
WHERE
    ROW BETWEEN CNT / 2 AND CNT / 2 + 1
;