select (SELECT TOTAL_VALUE FROM CONVENIENCE
where 
SURVEY_YEAR = '2019' AND 
KIND_CODE = '100'
ORDER BY TOTAL_VALUE
LIMIT 1 OFFSET (select (select COUNT(TOTAL_VALUE) AS SA_MEDIAN 
from CONVENIENCE
where 
SURVEY_YEAR = '2019' AND 
KIND_CODE = '100'
ORDER BY TOTAL_VALUE DESC) /2))
+
(SELECT TOTAL_VALUE FROM CONVENIENCE
where 
SURVEY_YEAR = '2019' AND 
KIND_CODE = '100'
ORDER BY TOTAL_VALUE
LIMIT 1 OFFSET (select ((select COUNT(TOTAL_VALUE) AS SA_MEDIAN 
from CONVENIENCE
where 
SURVEY_YEAR = '2019' AND 
KIND_CODE = '100'
ORDER BY TOTAL_VALUE DESC) /2)+1))/2 AS SA_MEDIAN