CREATE TABLE table_204_697 (id DECIMAL, "song" TEXT, "artist ( s ) " TEXT, "concert" DECIMAL, "film" DECIMAL, "1978 album" DECIMAL, "2002 album" DECIMAL)

which artist has the most concerts ?
SELECT "artist(s)" FROM table_204_697 ORDER BY "concert" DESC LIMIT 1
SELECT "artist(s)" FROM "table_204_697" ORDER BY "concert" DESC NULLS LAST LIMIT 1