Show me all the media types in tracks.
select t1.name from mediatype as t1 join track as t2 on t1.mediatypeid = t2.mediatypeid group by t2.mediatypeid
What is the most common one?
select t1.name from mediatype as t1 join track as t2 on t1.mediatypeid = t2.mediatypeid group by t2.mediatypeid order by count(*) desc limit 1
How about the least common one?
select t1.name from mediatype as t1 join track as t2 on t1.mediatypeid = t2.mediatypeid group by t2.mediatypeid order by count(*) asc limit 1