WITH VALS AS(
SELECT
	TOTAL_VALUE,
	ROW_NUMBER() OVER (ORDER BY TOTAL_VALUE) AS ROW_ID,
	(SELECT COUNT(0) FROM CONVENIENCE) AS CNT
FROM
	CONVENIENCE
WHERE
	KIND_CODE = '100'
	AND
	SURVEY_YEAR = 2019
)

SELECT 
	FLOOR(AVG(TOTAL_VALUE)) AS SA_MEDIAN
FROM
	VALS
WHERE
	ROW_ID BETWEEN CNT / 2.0 AND CNT / 2.0 + 1