hmmmm... regardless of [album]?
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It's the '~a' at the end causing that. my mistake
I think this gets you pretty close, but for these (multiple artists) albums getting in the way. They would be easy to exclude if you preferred.
here's the thinking behind the search above, as, if you know what it's doing, the results may make more sense or be better equipped to tweak things to suit:
[media type]=audio ~sort=[artist] ~nodup=[ag] ~dup=[artist] ~aoptional, self explanatory rules[ag] is the field we created earlier using the [artist] and [genre] field. If you have 20 'abba' tracks labelled 'Pop', 5 'abba' tracks labelled 'rock', and 1 'rod, jane & freddy' track labelled 'rubbish', this rule will leave you with 3 tracks...
1 Abba-Rock track
1 Abba-Pop track
1 Rod, Jane & Freddy-Rubbish trackthis keeps only duplicate artists, so Rod Jane & Freddy get dropped from the list(which is what you want, right?)
You now have a list containing only artists that have differing [genre] tags, showing you a single example of each different genre that exists for each of those artists.
This is close, but not close enough. to be able to mass edit each artist's genre field, you need to be able to see them. right-click > locate > album would get old pretty fast
enter the final piece of the string. ~a specifies that for the remaining files, all other files that match their [album] tags should also be listed.This works well for regular albums, but also reintroduces the flotsam generated by compilation albums. Adding:
-[Album Artist (auto)]=[/(Multiple Artists/)]
to the end of the search string should dramatically clean up things up, and return a list that is easy to read and work with, and that updates itself when it's loaded. (Hit F5 to reload)
Save the multi artist albums for another day!