Summation dependent on radio buttons

[Dazium]

I am working in a table which contains a portal linked to an "Invoice items" table; the portal displays invoice amounts, and also a radio button with two choices: "taxable" or "nontaxable/labor" (The radio button data actually comes from another table, "Billing_Codes.") I would like to insert two fields: one is a summation of all "taxable" invoices and the second is a summation of all "nontaxable/labor" invoices, as seen in the portal display. The following calculation I have set up is not operational:

Sum ( If (Billing_Codes::Taxable? = "Taxable" ; Invoice_Items::Amount ; 0) )

Any suggestions for calculating a sum of only certain items, depending on which radio button is selected, would be greatly appreciated! Thank you.

[Søren Dyhr]

You could do something like this:

http://www.fmforums.com/forum/showpost.php?post/253369/

--sd