[AnalogKid]

Thanks but the SQL is not a problem, I know well how to do that. I do wonder at the performance issues on a large song collection though. Would need checking on both SQLite and MySQL.

Also yet to convince myself if there is a need for 3 dates or just 2 (in addition to year).

If you store TYER already, then you probably need to also store any other date field that you are offering as a preference.
If you don't store all the other date fields, but only one 'fauxDate' then if the user chooses to use a new date preference from the UI, you'll have to rebuild that column which means scanning all the tags again.

Does that not leave with two options? TYER + FauxDate or TYER + all other selectable date fields.