I'm questioning my MySQL database best practices right now and trying to figure this out. I have a form that users will fill out YES/NO and in case of YES, there's an extra field to explain themselves. There's about 36 fields, and the table would be 1>1. Say 15 fields apply to (A) user, 8 apply to (B) user, 8 to (C) user and 5 apply to (D) user. Would it be better to have separate tables with 15, 8, 8 and 5 fields or one big 36 field table with some empty fields? I'm looking for performance and normalization.