I am trying to create a running total field and choose "on change of group" and "use a formula".

here is formula: Sum ({DataTable1.QTY}). When i save it, it tells me that there is error in this formula. after click "no" button, it tells me "a number field or currency amount field is required here".

I tried: Sum (CDbl ({DataTable1.QTY})) and got "a field required here" message.

I tried to use wizard to create this report. but when I try to create group total, there is no "SUM" option show up.

BTY, i am using .NET crystal report.
Please help.

Will