WITH A AS (
  SELECT TOTAL_VALUE,
         ROW_NUMBER() OVER (ORDER BY TOTAL_VALUE) AS row_num,
         COUNT(*) OVER () AS total_count
  FROM CONVENIENCE
  WHERE SURVEY_YEAR = 2019
    AND KIND_CODE = '100'
),
B AS (
  SELECT AVG(TOTAL_VALUE) AS SA_MEDIAN
  FROM A
  WHERE row_num IN ((total_count + 1) / 2, (total_count + 2) / 2)
)
SELECT ROUND(SA_MEDIAN, 0) AS SA_MEDIAN
FROM B;