WITH FILTER_TABLE
AS(
    SELECT
        *
    FROM
        CONVENIENCE
    WHERE
       SURVEY_YEAR = 2019
    	AND KIND_CODE = '100'
   )

SELECT
	ROUND(AVG(TOTAL_VALUE)) AS SA_MEDIAN
FROM
    (SELECT
        TOTAL_VALUE
      FROM
        FILTER_TABLE
      ORDER BY
        TOTAL_VALUE DESC
      LIMIT 2 - (SELECT COUNT(*) FROM FILTER_TABLE) % 2
      OFFSET (SELECT (COUNT(*) - 1) / 2 FROM FILTER_TABLE))
;