What are the names of artists who did not have an exhibition in 2004?
SELECT name FROM artist EXCEPT SELECT T2.name FROM exhibition AS T1 JOIN artist AS T2 ON T1.artist_id  =  T2.artist_id WHERE T1.year  =  2004
artists who did not have an exhibition in 2004 refers to using EXCEPT to exclude artists present in the exhibition in 2004; artists involved in exhibitions are identified through a JOIN between the artist and exhibition tables on artist_id; filtering exhibitions by year involves WHERE year = 2004;