select ROUND(avg(TOTAL_VALUE), 0)
from (select TOTAL_VALUE,
      Row_Number() over(order by TOTAL_VALUE) as Rn,
      count(*) over() as DataCount
      from CONVENIENCE
      WHERE SURVEY_YEAR = 2019  AND KIND_CODE = '100' ) a
      
where (mod(DataCount,2) = 0 and Rn in(DataCount/2,DataCount/2+1))
   or (mod(DataCount,2) = 1 and Rn = Ceil(DataCount/2.0));