Linking Listbox field to multiple dimensions

[#1]

Hi... I have two date fields order date and invoice date which reference to the order table and invoice table respectively. The user has a list box to select the month and year. Based on the month and year selection, I need the order placed and invoiced till that date. I am facing problem as to how do I link the two fields order date and invoice date to the list box field?

[#2]

then you make link table

LinkTable:

load

Orderdate as Date

resident Ordertable;

concatenate(LinkTable)

Load

Invoicedate as Date

resident Invoice table;

Link date field both of table;

Regards

Ashish