Table schema:
CREATE TABLE Songs (SongId VARCHAR); CREATE TABLE Band (lastname VARCHAR, id VARCHAR); CREATE TABLE Performance (bandmate VARCHAR, SongId VARCHAR)

Question: What is the last name of the musician that have produced the most number of songs?
SQL: SELECT T2.lastname FROM Performance AS T1 JOIN Band AS T2 ON T1.bandmate = T2.id JOIN Songs AS T3 ON T3.SongId = T1.SongId GROUP BY lastname ORDER BY COUNT(*) DESC LIMIT 1