What are the names of all songs that have a lower rating than some song of blues genre?
SELECT song_name FROM song WHERE rating  <  (SELECT max(rating) FROM song WHERE genre_is  =  "blues")
songs that have a lower rating than some song of blues genre refers to a subquery where the max rating of blues genre songs is compared to the ratings of all songs; song of blues genre refers to genre = 'blues'; lower rating refers to < comparison of rating.