calculations based on two different tables

[Umm Husina]

Hello All,
I have a field on one form based on one table called [Payer Paid YTD], and
on another field from another form based on another table (Services) called
[Payer Paid]. I want the PPYTD field textbox to show the sum of what the
payer has paid so far. I used this formula:

=Sum(Services![Payer Paid])
All get in the textbox when I view the form in Form View is #Error.
Please Help, Missy

 

[Ofer Cohen]

If there are few records for each customer, then use dsum to sum all the
records

=DSum("[Payer Paid]","Services","[CustomerInTable]=" & [CustomerInForm] )

If the customer is text field, add a single quote
=DSum("[Payer Paid]","Services","[CustomerInTable]='" & [CustomerInForm] &
"'")

If all the records for that customer are listed in the form, and only for
that customer use,
=Sum([Payer Paid])