with a as (select 
TOTAL_VALUE
from CONVENIENCE
where 
SURVEY_YEAR = 2019
and KIND_CODE='100'

limit 2 - ( select count(*) from convenience ) %2
offset (select (count(*) -1)/2
from convenience 
where 
SURVEY_YEAR = 2019
and KIND_CODE='100'
) )

select round(avg(TOTAL_VALUE)) from a;