with TARGET_DATA as (
    select
        row_number() over (order by TOTAL_VALUE) as ROW_NUM
        , count(*) over() as TOTAL_ROW
        , cast(TOTAL_VALUE as real) as TOTAL_VALUE
    from CONVENIENCE
    where SURVEY_YEAR=2019 and KIND_CODE='100'
)
select
    round(sum(case
        when TOTAL_ROW%2=0 and (ROW_NUM=TOTAL_ROW/2 or ROW_NUM=TOTAL_ROW/2 + 1) then TOTAL_VALUE
        when TOTAL_ROW%2=1 and ROW_NUM=round(TOTAL_ROW/2, 0) then TOTAL_VALUE
        else null
    end)/((TOTAL_ROW + 1)%2 + 1), 0) as SA_MEDIAN
from TARGET_DATA
;