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

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 FETCH FIRST 1 ROWS ONLY