MYSQL - Creating a View With Multiple Tables

Question

I am having trouble creating a view with multiple tables and junction tables.

This is where I'm at currently:

CREATE VIEW music_view AS 
SELECT recordings.rec_title, 
recordings.sales, 
artists.name as 'artists', 
genres.name as 'genres'
FROM 
recordings
JOIN artists
JOIN genres
JOIN rec_artist
WHERE artists.id = rec_artist.id
AND recordings.rec_id = rec_artist.rec_id
AND genres.id = recordings.genre_id;

Table schema:

recordings
rec_title (varchar)
rec_id (Primary Key)
sales (dec)
genre_id (Foreign Key)

genres
id (primary key)
name (varchar)

artists
id (primary key)
name (varchar)

rec_artist (junction table)
artist_id (primary key) 
rec_id (primary key)

I'm a little stumped as to where to proceed and am still figuring out MYSQL. Should I be doing subqueries instead of joins? My results are empty set. The question for this particular homework assignment is as follows:

Create a view with the titles and sales of all recordings, the names of their respective artists, and the name of the recording's genre. Sort alphabetically by the name of the genre. Within the same genre, sort alphabetically by the name of the artist. Within the same artist, sort by sales (highest first). Do not include NULL titles, genres, or artist names. Your view must have 4 columns.

Answer 1

You will need a query like the next one, using inner joins for joining the tables on the adequate columns:

CREATE VIEW music_view AS 
SELECT
    r.rec_title AS 'title',
    r.sales AS 'sales',
    a.name AS 'artist', 
    g.name AS 'genre'
FROM
    recordings AS r
INNER JOIN
    rec_artists AS ra ON ra.rec_id = r.rec_id
INNER JOIN
    artists AS a ON a.id = ra.artist_id
INNER JOIN
    genres AS g ON g.id = r.genre_id
ORDER BY
    'genre' ASC, 'artist' ASC, 'sales' DESC;

And for this last step:

Do not include NULL titles, genres, or artist names

You could add some restrictions on a where clause. Like this:

CREATE VIEW music_view AS 
SELECT
    r.rec_title AS 'title',
    r.sales AS 'sales',
    a.name AS 'artist', 
    g.name AS 'genre'
FROM
    recordings AS r
INNER JOIN
    rec_artists AS ra ON ra.rec_id = r.rec_id
INNER JOIN
    artists AS a ON a.id = ra.artist_id
INNER JOIN
    genres AS g ON g.id = r.genre_id
WHERE
    r.rec_title IS NOT NULL
AND
    a.name IS NOT NULL
AND
    g.name IS NOT NULL
ORDER BY
    'genre' ASC, 'artist' ASC, 'sales' DESC;