Formula Columnn in Matrix Report (Running Balance)

Question

Hi all. I hope somebody can help me.
I am working on a matrix report using multi-query data models. The report has 2 groups in the horizontal axis and 3 groups in the vertical axis. The intersection is not just a single row but may consist of multiple rows.
My problem is this. I want to create a column in the intersection which is obtained by using a column value from the lowest group in the vertical axis and a summary column obtained from the rows of the intersection.
Here's what my report looks like:
                    2002 (accross)                         2003
                    januar                    february (accross
                    payments      balance          paymenst     balance
2002 (down)
Januar (down)          
     Loan#1 10,000 500          9000          200          8800          
               500
     Loan#2     5000     100          4900          200          4700
February
     Loan#3     3500     0          3500          50          3450
     Loan#4     4200     0          4200          0          4200
As you can see, the loans are grouped by month and year. And the payments are grouped for the month and year too.
The data model is :
For Query 1 (Vertical Axis),
1st group - Loan Yr
2nd group - Loan Mo
3rd group - Loan # and amount
For Query 2 (Horizontal Axis)
1st group - Payment Yr
2nd group - Payment Mo
Intersecion /Detail Group - Payment Amount
My problem actually is how to compute for the running balance of the loan for each month in the horizontal axis. Ive already created a cross product summary to get the running total of the payments made for the month. I tried creating a formula column to for the running balance by subtracting it from the loan amount but i get the error "incompatible frequency"
I hope i have described my problem well and thanks for the help

Answer 1

The problem is that you're trying to reference dimension columns(loan Amount) in the calculation of matrix cell values. You can only reference other matrix cell values or cross product columns (summary, formula, placeholders) when calculating matrix cell values. Try moving the (loan Amount) column down to the matrix cell - something like:
For Query 1 (Vertical Axis),
1st group - G_LoanYear(LoanYr)
2nd group - G_LoanMonth(LoanMo)
3rd group - G_LoanNumber(Loan#)
For Query 2 (Horizontal Axis)
1st group - G_PaymentYear(PaymentYr)
2nd group - G_PaymentMonth(PaymentMo)
Intersecion /Detail Group - G_Details(PaymentAmount, LoanAmount)
Then create the following Matrix summary columns:
A running summary - CS_Payments:
- Product Order: G_LoanYear G_LoanMonth G_LoanNumber G_PaymentYear G_PaymentMonth
- Source: PaymentAmount
- Function: Sum
- Reset At: G_LoanNumber
The total amount per loan - CS_TotalPayment:
- Product Order: G_LoanYear G_LoanMonth G_LoanNumber
- Source: LoanAmount
- Function: First
- Reset At: G_LoanNumber
The value of the loan after each payment - CF_Countdown:
- Product Order: G_LoanYear G_LoanMonth G_LoanNumber G_PaymentYear G_PaymentMonth
- PL/SQL Formula:
function CF_CountdownFormula return Number is
begin
return(:CS_TotalPayment - :CS_Payments);
end;
You should then be able to display "CF_Payments" and "CF_Countdown" in the matrix cell to show how much has been paid and how much is still owed.
You can still have another "loan amount" as a dimension column - you just don't need to use it when calculating the values in the cell.