Split number into rows so that they sum up to the original number - sql-server

Question

I have a table [tbl] with money values
id mon
1 10.17
2 36.00
I need to split these values into rows by a set of specific ranges [1.00,10.00,25.00]. The sum of the new values grouped by id will equal the original value.
id mon sum
1 1.00 1.00
1 9.17 10.17
2 1.00 1.00
2 10.00 11.00
2 25.00 36.00
Is there any way to do this without using a cursor?

Answer 1

Here's one way to do it:
;with CTE as (select t2.value, t1.id, sum(t2.value)
over (partition by t1.id order by t2.value asc) as total
from table1 t1 join table2 t2 on t1.mon >= t2.limit
)
select id, value, total from CTE
union all
select t1.id, t1.mon - c.total, t1.mon
from table1 t1
outer apply (select top 1 id, total from CTE c
where c.id = t1.id order by c.value desc) c
where t1.mon > c.total
order by 1,3
This uses additional table that has the limits stored to join with the original data and then uses running total in a CTE and joins that to the original table to get the remaining amounts
You can test the example in SQL Fiddle

Answer 2

Here is my attempt using window functions and CROSS APPLY:
;WITH Cte(s) AS(
SELECT CAST(1 AS MONEY) UNION ALL
SELECT 10 UNION ALL
SELECT 25
)
,CteRange AS(
SELECT
s,
e = SUM(s) OVER(ORDER BY s)
FROM Cte
)
SELECT
t.id,
mon = CASE WHEN t.mon > x.e THEN x.s ELSE mon - LAG(x.e) OVER(PARTITION BY t.id ORDER BY x.s) END,
[sum] = CASE WHEN t.mon < x.e THEN t.mon ELSE x.e END
FROM tbl t
CROSS APPLY(
SELECT * FROM CteRange
)x
WHERE t.mon > x.s
UNION ALL
SELECT
t.id,
mon = t.mon - x.e,
[sum] = t.mon
FROM tbl t
CROSS APPLY(
SELECT TOP 1 e
FROM CteRange
ORDER BY e DESC
)x(e)
WHERE t.mon > e
ORDER BY t.id, mon
SQL Fiddle

Answer 3

This works for your given example data, you just need to predefine ranges all by yourself (I've used CROSS JOIN VALUES, but this can be done however you want/prefer). I think that's not an issue. I've used running SUM and analytic functions to achieve that.
DECLARE #tbl TABLE
(
id INT IDENTITY (1, 1)
, mon MONEY
);
INSERT INTO #tbl (mon)
VALUES (10.17), (36.00);
SELECT id
, [sum] - SUM(lagRange) OVER (PARTITION BY ID ORDER BY rangeId) AS mon
, [sum]
FROM (
SELECT id, rangeId
, LAG(rangeValue, 1, 0) OVER (PARTITION BY ID ORDER BY rangeId) AS lagRange
, CASE
WHEN SUM(rangeValue) OVER (PARTITION BY ID ORDER BY rangeId) > mon THEN mon
ELSE SUM(rangeValue) OVER (PARTITION BY ID ORDER BY rangeId)
END AS [sum]
FROM #tbl
CROSS JOIN (VALUES ((1), (1.00)), ((2), (10.00)), ((3), (25.00))) AS T(rangeId, rangeValue)
WHERE rangeValue <= mon
) AS T;
Results:
id mon sum
-----------------
1 1.00 1.00
1 9.17 10.17
2 1.00 1.00
2 10.00 11.00
2 25.00 36.00