CREATE TABLE tags (index DECIMAL, id DECIMAL, tag TEXT)
CREATE TABLE torrents (groupname TEXT, totalsnatched DECIMAL, artist TEXT, groupyear DECIMAL, releasetype TEXT, groupid DECIMAL, id DECIMAL)

Which artist/group is most productive?
SELECT artist FROM torrents GROUP BY artist ORDER BY COUNT(groupname) DESC LIMIT 1
SELECT "artist" FROM "torrents" GROUP BY "artist" ORDER BY COUNT("groupname") DESC NULLS LAST LIMIT 1