SELECT ROUND(AVG(TOTAL_VALUE)) as SA_MEDIAN
FROM (
   SELECT TOTAL_VALUE
      FROM CONVENIENCE
      WHERE SURVEY_YEAR = 2019
      AND KIND_CODE = 100
      ORDER BY TOTAL_VALUE
      LIMIT 2 - ((SELECT COUNT(*) FROM CONVENIENCE) % 2) -- odd 1, even 2
      OFFSET (SELECT (COUNT(*) - 1) / 2 FROM CONVENIENCE)
)
;