I am needing to Calculate the start/end Balances by day for each Site/Department. I have a source table call it “Source” that has the following fields:
Site
Department
Date
Full_Income
Income_To_Allocate
Payments_To_Allocate
There are 4 Sites (SiteA/SiteB/SiteC/SiteD), Sites B-D have only 1 department and Site A has 10 departments.
This table is “mostly” a daily summary. I say “mostly” as the daily detail from 2018 was lost and instead we just have the monthly summary inputted as one entry on the last day of the month. For 2018 there is only data going back to September. From 1/1/2019 the summary is actually daily.
Any Income in the Full_Income field will be given to that Site/Department at 100% value. Any Income in the Income_To_Allocate field will be spread among all the Site/Departments using the below logic:
(
(Prior_Month_Site_Department_ Balance+ This_Month_Site_Department_Full_Income)
/
(Prior_Month_All_Department_Balance + This_Month_All_Department_Full_Income)
)
*
(This_Month_All_Department_Income_to_Allocate)
Any Payments in the Payments_to Allocate) field will be spread among all the Site/Departments using the below logic:
(
(Prior_Month_Site_Department_ Balance+ This_Month_Site_Department_Full_Income)
/
(Prior_Month_All_Department_Balance + This_Month_All_Department_Full_Income)
)
*
(This_Month_All_Department_Payments_to_Allocate)
The idea behind these pieces of logic is to spread the allocated pieces based on the % of business each Site/Department did when looking at the Full_Income data.
The Balance would be calculated with this logic:
Start Balance:
Prior day Ending Balance
Ending Balance:
Prior day Ending Balance + (Site_Department_Full_Income) + (Site_Department_Allocated_Income)- (SiteDepartment_Allocated_Income)
I have tried to do things using the lag function to grab the prior info that I am needing for these calculations. I always get real close but I always wind up stuck on the fact the Ending Balance is calculated using the post spread values for the allocated income and reseeds while the calculation for the spread is using the prior month balance info. This ends up being almost circular logic but with a finite start point. I am at a loss for how to make this work.
I am using SQL Server 2012. Let me know if you need any more details.