What is the name for the artist with the most number of exhibitions?
select t2.name from exhibition as t1 join artist as t2 on t1.artist_id = t2.artist_id group by t1.artist_id order by count ( * ) desc limit 1
What country is he from?
select t2.country from exhibition as t1 join artist as t2 on t1.artist_id = t2.artist_id group by t1.artist_id order by count ( * ) desc limit 1
Who is the artist with the least number of exhibitions?
select * from exhibition as t1 join artist as t2 on t1.artist_id = t2.artist_id group by t1.artist_id order by count ( * ) limit 1