MySQL isn't my strong point, but normally I do all right. This one is beyond my knowledge though. Background: I'm starting a website akin to Identifont to identify types of aircraft (737, A320, etc) based on a series of questions: wing shape, number and type of engines, and so forth. Basically, the site content will be contributed by a group of privileged users who can add and categorize new aircraft and attributes. New attributes will be needed to distinguish between similar aircraft to ensure that the user isn't presented with 40 possible candidates based on a given set of responses. I need a query that can identify these lumps of data, sets of user responses that would result in a large number of possibilities returned. That information would then be presented in an admin panel, with the largest lumps listed first. More details on the problem here and the database here. I'm sorry if the question is a bit confused, that's probably just the questioner's confusion coming across.