WITH aa AS (
SELECT
    ROW_NUMBER() OVER (ORDER BY TOTAL_VALUE) AS n,
    TOTAL_VALUE
FROM
    CONVENIENCE
WHERE
    SURVEY_YEAR = 2019
    AND KIND_CODE = '100'
)

SELECT
    ROUND(AVG(TOTAL_VALUE), 0) AS SA_MEDIAN
FROM
    aa
WHERE
    abs(n - (SELECT COUNT(1)*1.0 / 2 FROM CONVENIENCE)) < 1