SELECT
    ROUND(AVG(TOTAL_VALUE), 0) AS SA_MEDIAN
FROM
    (
        SELECT
            TOTAL_VALUE,
            Row_Number() OVER(
                ORDER BY
                    TOTAL_VALUE
            ) AS RowNumber,
            COUNT(*) OVER() AS DataCount
        FROM
            CONVENIENCE
        WHERE
            SURVEY_YEAR = 2019
            AND KIND_CODE = '100'
    ) AS base
WHERE
    (
        MOD(DataCount, 2) = 0
        AND RowNumber IN (DataCount / 2, DataCount / 2 + 1)
    )
    OR (
        MOd(DataCount, 2) = 1
        AND RowNumber = Ceil(DataCount / 2.0)
    );