ms access training courses in london - Access Advanced

Im trying to create an Aged Debt Report from a table in Access.

My fields are Customer Number, Invoice Number, Invoice Amount and Invoice Date. A customer would have multiple invoices created on various dates. E.g

Customer Number Invoice Number Invoice Amount Invoice Date
123 Inv454 200 2/1/07
123 Inv455 123 8/2/07
123 Inv456 320 12/3/07
456 Inv457 100 6/2/07
456 Inv458 342 2/3/07
789 Inv459 678 9/1/07

The user will enter a parameter (usually the last day of the month).

SO each cusomer will show in one line only, their current month invoices, invoices outstanding for 30 days and invoices outstanding for 60 days.

I need to create formulas:

1. That will calculate invoices that fall in the current month (pointing to the parameter).

2. That will calculate invoices that fall within 30 days from the invoice date

3. That will calculate invoices that fall within 60 days from the invoice date

If the user entered 31/3/07, the report should look tlike this

Customer Number Current 30 days 60 days
123 320 123 200
456 342 100 0
789 0 0 678