WITH tmp as(
SELECT
    TOTAL_VALUE   
FROM
    CONVENIENCE
WHERE
    KIND_CODE = '100'
    AND
    SURVEY_YEAR = 2019
ORDER BY
    TOTAL_VALUE
LIMIT 2 - (SELECT COUNT(*) % 2 FROM CONVENIENCE WHERE KIND_CODE = '100' AND SURVEY_YEAR = 2019)
OFFSET (SELECT (COUNT(*) - 1)/2 FROM CONVENIENCE WHERE KIND_CODE = '100' AND SURVEY_YEAR = 2019)
)

SELECT
    ROUND(AVG(TOTAL_VALUE)) AS SA_MEDIAN
FROM
    tmp
;