with a as (select 
    TOTAL_VALUE
    from CONVENIENCE
    where 
    SURVEY_YEAR = 2019
    and KIND_CODE='100'
    limit 2 - ( select count(*) from convenience
    where 
    SURVEY_YEAR = 2019
    and KIND_CODE='100'
    ) %2
    offset (select (count(*) -1)/2
    from convenience 
    where 
    SURVEY_YEAR = 2019
    and KIND_CODE='100'
    ) )
    select round(avg(TOTAL_VALUE)) SA_MEDIAN from a;