search query/analysis of multiple fields
I am using FileMaker Pro 10 to analyze voter registration data. Each voter in the database is assigned a unique ID number. The database also contains four fields which represent four different election dates, lets call them "Election A", "Election B", "Election C" and "Election D". Each of the four fields contains either a "V" (voted) or "DV" (didn't vote) to indicate whether the voter voted in the particular election or not. I want to run a search query on those four fields (representing the four election dates) to identify the universe of voters that voted in exactly one of the four elections (but no more than one election). Any ideas on how this could be done?