Return the name and country corresponding to the artist who has had the most exhibitions.
SELECT T2.name , 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
artist who has had the most exhibitions refers to MAX(COUNT(exhibition)); name and country of the artist refers to SELECT name, country; JOIN is used to combine rows from two or more tables based on a related column between them.