DSUM expression buil

[Bob]

Hello,

I am working on building a running total on a form. I
have used DSum before but now i need to expand the
expression criteria to include a AND condiditon.

In my table is a field to hold the count value (DAYS), and
a field that indicates the type of count(DUTY CODE). Both
tables are being linked via the key values.

When i get to the Expression criteria, i normally do the
link beteen the key values, so that I only get the total
for the from i am currently looking at. however, now, I
also want to add another qualiefer (DUTY CODE). So, i
only want a running total where the key values = each
other and the DUTY CODE = a specific value.

How do I set that up and format that?

Thanks
Bob