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

SELECT DISTINCT
    nth_value(TOTAL_VALUE, (select count(*) from target_year)/2) OVER(RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS SA_MEDIAN
FROM
    target_year
;