I have a control on a form for which the data source is an autonumber field in a table. This number is used as a purchase order number in my database, however my PO numbers are all prefixed with the letters "CC". The control pointing to the data field is hidden in my form, and I have an unbound control which contains the expression ="CC" & [PONumber] so that the number will display on my form as CC12345 for instance.
I have many records for which a PO number has not been assigned yet, and they all display the "CC" with no trailing PO number. Is there a way for me to suppress the "CC" in my expression so that it will only display in the records which actually have PO numbers in them?