WITH CON_2019 AS (
    select SURVEY_YEAR, PF_CODE, KIND_CODE, TOTAL_VALUE 
    from CONVENIENCE
    WHERE SURVEY_YEAR=2019
      and KIND_CODE=100
    order by TOTAL_VALUE desc
)
select ROUND(AVG(TOTAL_VALUE))
from (select TOTAL_VALUE
        from CON_2019
       order by TOTAL_VALUE desc
       LIMIT 2 - (select count(*)%2 from CON_2019)
      OFFSET (select (count(*)-1)/2 from CON_2019)
     )
;