Count other fields
I have a filemaker pro 12 database of customers.
The different products we sell each given a different field - and each one has a choice of entries: Paid, Reserved or is left blank.
I would like to be able to tell which customers have bought a previous product, and which ones are first time buyers.
Can I do a count/summary/calculation in a new field that will tell me how many fields contain 'paid' a particular record has? I have tried to use various formulae - including PatternCount and Sum but seem to be getting it wrong.