with vCount as
(select 
	 count(*) cnt
	from CONVENIENCE c
	where c.SURVEY_YEAR = 2019
	and c.KIND_CODE = '100')
,cRank as
(select 
	 TOTAL_VALUE
	,rank() over(order by TOTAL_VALUE desc) rnk
	from CONVENIENCE c
	where c.SURVEY_YEAR = 2019
	and c.KIND_CODE = '100')
select SA_MEDIAN
from (select 
		round(sum(r.TOTAL_VALUE)/2,0) as SA_MEDIAN
		from cRank r
		cross join vCount c
		where mod(c.cnt,2)=0
		and r.rnk in (c.cnt/2-1,c.cnt/2+1)
		union all
		select 
		round(sum(r.TOTAL_VALUE)/2,0) as SA_MEDIAN
		from cRank r
		cross join vCount c
		where mod(c.cnt,2)=1
		and r.rnk in (c.cnt/2-0.5))
where SA_MEDIAN is not null