text: /* Show all albums. */
  SELECT * FROM album;
  
  /* Show all albums made between 1975 and 1990. */
  SELECT * FROM album
  WHERE release_year >= 1975
  AND release_year <= 1990;
  
  /* Show all albums whose names start with Super D */
  SELECT * FROM album
  WHERE title LIKE "Super D%";
  
  /* Show all albums that have no release year. */
  SELECT * FROM album
  WHERE release_year IS NULL;
  
  /* Show all track titles from Super Funky Album. */
  SELECT title FROM track 
  WHERE album_id = (SELECT id FROM album
                    WHERE title="Super Funky Album");
  
  /* Same query as above, but rename the column from title to Track_Title in the output. */
  SELECT title AS Track_Title FROM track
  WHERE album_id = (SELECT id FROM album
                    WHERE title="Super Funky Album");
  
  /* Select all album titles by Han Solo. */
  SELECT title FROM album
  WHERE id = (SELECT album_id FROM artist_album
              WHERE artist_id = (SELECT id FROM artist
              	               WHERE name = "Han Solo"));
  
  /* Select the average year all albums were released. */
  SELECT AVG(release_year) FROM album;
  
  /* Select the average year all albums by Leia and the Ewoks were released. */
  SELECT AVG(release_year) FROM album
  WHERE id = (SELECT album_id FROM artist_album
              WHERE artist_id = (SELECT id FROM artist
              	               WHERE name = "Leia and the Ewoks"));
  
  /* Select the number of artists. */
  SELECT DISTINCT COUNT(id) FROM artist;
  
  /* Select the number of tracks on Super Dubstep Album. */
  SELECT DISTINCT COUNT(id) FROM track
  WHERE album_id = (SELECT id FROM album
                    WHERE title = "Super Dubstep Album")