CREATE TABLE band (id DECIMAL, firstname TEXT, lastname TEXT)
CREATE TABLE performance (songid DECIMAL, bandmate DECIMAL, stageposition TEXT)
CREATE TABLE vocals (songid DECIMAL, bandmate DECIMAL, type TEXT)
CREATE TABLE songs (songid DECIMAL, title TEXT)
CREATE TABLE instruments (songid DECIMAL, bandmateid DECIMAL, instrument TEXT)
CREATE TABLE albums (aid DECIMAL, title TEXT, year DECIMAL, label TEXT, type TEXT)
CREATE TABLE tracklists (albumid DECIMAL, position DECIMAL, songid DECIMAL)

What is the last name of the musician that have produced the most number of songs?
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
SELECT "T2"."lastname" FROM "performance" AS "T1" JOIN "band" AS "T2" ON "T1"."bandmate" = "T2"."id" JOIN "songs" AS "T3" ON "T1"."songid" = "T3"."songid" GROUP BY "lastname" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1