Retrieve open invoice amount from selected date (master Cal.)

[#1]

I have a table which contains two dates, a duedate and a payment date and an invoice amount.

My client wants to know the open invoice amount on a specified date or a period .

I want to now how i can accomplish this ?

I've created a master calendar so the client can pick any date he wants.

How can i connect these dates so that we can see the open invoice amount on that date or period .

See the table

With regards,

Ron 

[MK_QSL]

are all these invoices paid?

If yes, please provide some data with unpaid invoices also.

[#3]

Yes, all paid. We want to know at any given day, what was the open amount

Ron