with
  a as (
    select
      count(*) as cnt
    from
      CONVENIENCE
    where
      SURVEY_YEAR = 2019
      and KIND_CODE = '100'
  ),
  b as (
    select
      TOTAL_VALUE,
      rank() over (
        order by
          total_value,
          KIND_CODE,
          survey_year,
          pf_code,
          kind_code
      ) -1 as rnk
    from
      CONVENIENCE
    where
      SURVEY_YEAR = 2019
      and KIND_CODE = '100'
    order by
      1
  )
select
  -- total_value,
  round(sum(cast(total_value as real) / cast((a.cnt+1) % 2 + 1 as real)),0) as SA_MEDIAN
from
  b,
  a
where
  b.rnk = cnt / 2
  or (
    a.cnt % 2 = 0
    and b.rnk = cnt / 2 -1
  )