FIndWeightedMedian.sql

/*
drop table if exists #data
select min,max, value = 1e* (abs(binary_checksum(newid()))%1000)
into #data
from (values(0, 9)
    ,(10, 19)
    ,(20, 29)
    ,(30, 39)
    ,(40, 59)
    ,(60, 70)
    ,(70, null)) d(min,max)
*/

select * from #data
select * 
,median = max(iif(sign(midp - rsum) < sign(midp - rsum + value) then min + ((midp - rsum + value) / nullif(value, 0)) * (max - min),null)) over()
from (
select  min,
        max,
        value,
        rsum = sum(value) over (order by min rows unbounded preceding),
        midp = sum(value) over () / 2
from #data d
) z