How to Save SUM() to Variable?

thenicespider

In FR2 I can do this:

on Memo3:
[Total]
begin
Total:= SUM([datasetTEST."AMOUNT"]);
end;


How to do this in FR3?

I try this :
Memo3 contain: [Total]
procedure Memo3OnBeforePrint(Sender: TfrxComponent);
begin
Set ('Total', SUM(<frxdseTEST."AMOUNT">,DetailData1);
// ERROR: Set ('Total', VartoStr(<SUM(<frxdseTEST."AMOUNT">,DetailData1)>);
end;

Nothing appear!