SQL Server 2012 :: Divide Amount Between Months

Background:

Void Start Date: When a property becomes empty or vacant

Let Date: When the property is filled in again

I have the sample data below and like to show the void loss per month basis as below:

1) Allocate the amount from voidloss column between months based on voiddays:

for example for propcode 3698 the amount 13,612.56 needs to be divided between September and October based on the VoidDays. i.e of the 39 voiddays, 25 where in September and 14 in October hence 8726 will be allocated to September and 4886.56 to October

2) After allocating the amount sum the amount by controlgroup and total the voiddays per month. It will be great if we can divide the voiddays between months and sum them by controlgroup as well.

So in the end result we should have

ControlGroup, Month, Year, VoidLoss, VoidsdayinMonth
106 September 2014 8726 25
106 October 2014 4886.56 14
106 December 2014 2940 7

Declare @voidloss Table
( History_IND INT
,PropCode VARCHAR(10)
,VoidCategory VARCHAR(10)
,ControlGroup VARCHAR(10)
,VoidStartDate date

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