with 
TBL_RN as (
select
    TOTAL_VALUE
    ,row_number() over (order by TOTAL_VALUE) as RN
from
    CONVENIENCE
where
    KIND_CODE='100'
    and SURVEY_YEAR='2019'
)

,TBL_CNT as (
select 
    count(*) as CNT
from
    TBL_RN
)

,TBL_COL_TO_PICK as (
select
    case
        when CNT%2=1 then (CNT-1)/2
        when CNT%2=0 then CNT/2
        end as PICK
from
    TBL_CNT
union all
select
    case
        when CNT%2=1 then null
        when CNT%2=0 then CNT/2+1
        end as PICK
from
    TBL_CNT
)


select
    round(avg(P.TOTAL_VALUE)) as SA_MEDIAN
from
    TBL_RN P
    inner join
        TBL_COL_TO_PICK S
        on
            P.RN=S.PICK
;