As you found, you can only sum field(s) that are in the form's RecordSource.
Having the calculated field in the query is a good solution.
The alternative is to repeat the actual fields in the Control Source, e.g.:
=Sum([Credit] - [Debit])
--
Allen Browne - Microsoft MVP. Perth, Western Australia.
Tips for Access users -
http://allenbrowne.com/tips.html
Reply to group, rather than allenbrowne at mvps dot org.
"Roger" <lesperancer@natpro.com> wrote in message
news:8c7a509f.0409222003.505801b8@posting.google.c om...[color=blue]
> I've got a continuous form based on a query
> the first 2 controls on the form are bound to columns in the query
> a third control (paymentAmount) is unbound
> I have a total control in the footer, where the control source is
> =sum(paymentAmount)
>
>
> this displays #Error#
>
> but if I temporarily change my query to add a paymentAmount column
> with a value of 1, and I change the control source of the
> paymentAmount control to 'paymentAmount', (so the control is called
> paymentAmt and the control source is paymentAmt), my total control in
> the footer displays the correct total
>
> now if I change the name of the control to paymentAmount2, with a
> control source of paymentAmount, the total control is correct
>
> if I change the control source of the total control to
>
> =sum(paymentAmount2)
>
> my error returns....
>
> why does it sum only a control source ?
> how do I get to sum the contents of a control ?[/color]
