SQL Select up to a certain sum - sql

Question

I have been trying to figure out a way to write a SQL script to select a given sum, and would appreciate any ideas given to do so.
I am trying to do a stock valuation based on the dates of goods received. At month-end closing, the value of my stocks remaining in the warehouse would be a specified sum of the last received goods.
The below query is done by a couple of unions but reduces to:
SELECT DATE, W1 FROM Table
ORDER BY DATE DESC
Query result:
Row DATE W1
1 2019-02-28 00:00:00 13250
2 2019-02-28 00:00:00 42610
3 2019-02-28 00:00:00 41170
4 2019-02-28 00:00:00 13180
5 2019-02-28 00:00:00 20860
6 2019-02-28 00:00:00 19870
7 2019-02-28 00:00:00 37780
8 2019-02-28 00:00:00 47210
9 2019-02-28 00:00:00 32000
10 2019-02-28 00:00:00 41930
I have thought about solving this issue by calculating a cumulative sum as follows:
Row DATE W1 Cumulative Sum
1 2019-02-28 00:00:00 13250 13250
2 2019-02-28 00:00:00 42610 55860
3 2019-02-28 00:00:00 41170 97030
4 2019-02-28 00:00:00 13180 110210
5 2019-02-28 00:00:00 20860 131070
6 2019-02-28 00:00:00 19870 150940
7 2019-02-28 00:00:00 37780 188720
8 2019-02-28 00:00:00 47210 235930
9 2019-02-28 00:00:00 32000 267930
10 2019-02-28 00:00:00 41930 309860
However, I am stuck when figuring out a way to use a parameter to return only the rows of interest.
For example, if a parameter was specified as '120000', it would return the rows where the cumulative sum is exactly 120000.
Row DATE W1 Cumulative Sum W1_Select
1 2019-02-28 00:00:00 13250 13250 13250
2 2019-02-28 00:00:00 42610 55860 42610
3 2019-02-28 00:00:00 41170 97030 41170
4 2019-02-28 00:00:00 13180 110210 13180
5 2019-02-28 00:00:00 20860 131070 9790
----------
Total 120000

Answer 1

This just requires some arithmetic:
select t.*,
(case when running_sum < #threshold then w1
else #threshold - w1
end)
from (select date, w1, sum(w1) over (order by date) as running_sum
from t
) t
where running_sum - w1 < #threshold;
Actually, in your case, the dates are all the same. That is a bit counter-intuitive, but you need to use the row for this to work:
select t.*,
(case when running_sum < #threshold then w1
else #threshold - w1
end)
from (select date, w1, sum(w1) over (order by row) as running_sum
from t
) t
where running_sum - w1 < #threshold;
Here is a db<>fiddle.