SELECT
    CASE WHEN ( SELECT COUNT(*) FROM CONVENIENCE WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100' ) % 2 = 0
            THEN (
                SELECT 
                    ROUND(AVG(X.TOTAL_VALUE)) AS SA_MEDIAN
                FROM (
                    SELECT TOTAL_VALUE
                        ,ROW_NUMBER() OVER(
                            ORDER BY TOTAL_VALUE DESC) AS NUM
                    FROM CONVENIENCE
                    WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100'
                    ) X
                WHERE X.NUM = ( SELECT COUNT(*) FROM CONVENIENCE WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100' ) / 2
                    OR X.NUM = ( SELECT COUNT(*) FROM CONVENIENCE WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100' ) / 2 + 1
                )
          WHEN ( SELECT COUNT(*) FROM CONVENIENCE WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100' ) % 2 = 1
            THEN (
                SELECT 
                    ROUND(AVG(Y.TOTAL_VALUE)) AS SA_MEDIAN
                FROM (
                    SELECT TOTAL_VALUE
                        ,ROW_NUMBER() OVER(
                            ORDER BY TOTAL_VALUE DESC) AS NUM
                    FROM CONVENIENCE
                    WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100'
                    ) Y
                WHERE Y.NUM = ( SELECT COUNT(*) FROM CONVENIENCE WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100' ) / 2 + 1
                )
          END
FROM CONVENIENCE
WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100'