how to display quantity of those records are only on current month

[cuongvt]

I have a form "delivery control" with 3 fields:
1. productid
2. date delivered
3.deliveryquantity

I create an unbound field in its footer and set it by =Sum([deliveryquantity]).
And the total quantity of all products in all time is displays.

But I want it to display sum quantity of those records are only on current month and by each productID.
for example: in this month, I want it to display quantity of those records are only on august. in next month, I want it to display quantity of those records are only on september.
I post my file for you for reference. (using access 2003)
Please help me. I need your help.
many thanks.

 

[Mile-O]

Criteria on the date field for current month:

Between DateSerial(Year(Date()), Month(Date()), 1) And Date()

 

[cuongvt]

I set total field of that form to: Sum([deliveryquantity]) Between DateSerial(Year(Date()),Month(Date()),1) And Date()
but it don't work. I'm sorry, could you describe how to do it in detail, I'm new to access.
(note that it is a form, not a query)
many thanks