Sum a calculated query, without GroupBy totals?

[infinite2006]

Im trying to run the following calculated query:

Total Value on order: Sum([Purchase Price])

I want to sum the total of all the purchase prices together so I know the total value on order. I keep getting an error: "You tried to execute a query that does not include the specified expression Purchase Order' as part of an aggregate function

 

[Galaxiom]

Use this ControlSource for a textbox in the footer of the form or report.

=Sum([Purchase Price])

 

[infinite2006]

Use this ControlSource for a textbox in the footer of the form or report.

=Sum([Purchase Price])

I'll try that Galaxiom and let you know how I get on, any idea why I have to insert into footer, not just run it inside my main table srtuctured query summary form