IF statement in an expression

[#1]

I am trying to wirte an IF statement in an expression to either Add or subtract sales and costs depeneding on whether the sales figure is a '+' or a '-'. my code so far is

Sum(Aggr(If([Sales]='+',  Sum([Sales Amount (Actual)])-([InvoiceLine_UnitCost]*[Invoiced Quantity]) ,

         If([Sales]='-', Sum([Sales Amount (Actual)])+([InvoiceLine_UnitCost]*[Invoiced Quantity])))))

The [Sales] tag is an existing column in the chart.

[danieloberbilli]

Please attach an example qvw file to have  a closer look

[christian77]

Hi.

Use set analysis.

[#4]

ok. Just trying to upload. For some reason the ability to upload to the discussion forum is greyed out in my menu.