Alternative: Sql - SELECT rows until the sum of a row is a certain value - sql

Question

My question is very similar to my previous one posted here:
Sql - SELECT rows until the sum of a row is a certain value
To sum it up, I need to return the rows, until a certain sum is reached, but the difference this time, is that, I need to find the best fit for this sum, I mean, It doesn't have to be sequential. For example:
Let's say I have 5 unpaid receipts from customer 1:
Receipt_id: 1 | Amount: 110€
Receipt_id: 2 | Amount: 110€
Receipt_id: 3 | Amount: 130€
Receipt_id: 4 | Amount: 110€
Receipt_id: 5 | Amount: 190€
So, customer 1 ought to pay me 220€.
Now I need to select the receipts, until this 220€ sum is met and it might be in a straight order, like (receipt 1 + receipt 2) or not in a specific order, like (receipt 1 + receipt 4), any of these situations would be suitable.
I am using SQL Server 2016.
Any additional questions, feel free to ask.
Thanks in advance for all your help.

Answer 1

This query should solve it.
It is a quite dangerous query (containing a recursive CTE), so please be careful!
You can find some documentation here: https://www.essentialsql.com/recursive-ctes-explained/
WITH the_data as (
SELECT *
FROM (
VALUES (1, 1, 110),(1, 2,110),(1, 3,130),(1, 4,110),(1, 5,190),
(2, 1, 10),(2, 2,20),(2, 3,200),(2, 4,190)
) t (user_id, receipt_id, amount)
), permutation /* recursive used here */ as (
SELECT
user_id,
amount as sum_amount,
CAST(receipt_id as varchar(max)) as visited_receipt_id,
receipt_id as max_receipt_id,
1 as i
FROM the_data
WHERE amount > 0 -- remove empty amount
UNION ALL
SELECT
the_data.user_id,
sum_amount + amount as sum_amount,
CAST(concat(visited_receipt_id, ',', CAST(receipt_id as varchar))as varchar(max)) as visited_receipt_id,
receipt_id as max_receipt_id ,
i + 1
FROM the_data
JOIN permutation
ON the_data.user_id = permutation.user_id
WHERE i < 1000 -- max 1000 loops, means any permutation with less than 1000 different receipts
and receipt_id > max_receipt_id -- in order that sum in komutatif , we can check the sum in any unique order ( here we take the order of the reciept_id in fact we do not produce any duplicates )
-- AND sum_amount + amount <= 220 -- ignore everything that is bigger than the expected value (optional)
)
SELECT *
FROM permutation
WHERE sum_amount = 220
in order to select only one combination per user_id, replace the last three lines of the previous query by
SELECT *
FROM (
SELECT *, row_number() OVER (partition by user_id order by random() ) as r
FROM permutation
WHERE sum_amount = 220
) as t
WHERE r = 1

Answer 2

IF your target is to sum only 2 receipts in order to reach your value, this could be a solution:
DECLARE #TARGET INT = 220 --SET YOUR TARGET
, #DIFF INT
, #FIRSTVAL INT
SET #FIRSTVAL = (
SELECT TOP 1 AMOUNT
FROM myRECEIPTS
ORDER BY RECEIPT_ID ASC
)
SELECT TOP 1 *
FROM myRECEIPTS
WHERE AMOUNT = #TARGET - #FIRSTVAL
ORDER BY RECEIPT_ID ASC

Answer 3

this code will do it:
declare #sum1 int
declare #numrows int
set #numrows= 1
set #sum1 =0
while (#sum1 < 10)
begin
select top (#numrows) #sum1=sum(sum1) from receipts
set #numrows +=1
end
select top(#numrows) * from receipts