SQLite3での外部キーの関連付け

Question

保存されているすべてのトラックの中で最も長い10の曲を保持する新しいプレイリストを作成するだけです。ここで私のコードと下のスキーマは、Colud誰かがPlaylistTrackにPlaylistとTrackのforiegnキーを関連付ける方法を説明してください。

INSERT INTO Playlist (PlaylistID, Name) 
VALUES (19, 'Background Music'); 

SELECT TrackID, Name, Millisecond 
FROM Track 
ORDER BY Millisecond DESC 
LIMIT 10 
JOIN Track.TrackID = PlaylistTrack.TrackID 
WHERE Playlist.Name = 'Background Music'; 

SCHEMA：

CREATE TABLE Playlist 
(
    PlaylistID INTEGER PRIMARY KEY NOT NULL, 
    Name TEXT 
); 



    CREATE TABLE PlaylistTrack 
    (
     PlaylistID INTEGER NOT NULL, 
     TrackID INTEGER NOT NULL, 
     PRIMARY KEY (PlaylistID, TrackID), 
     FOREIGN KEY (PlaylistID) REFERENCES Playlist (PlaylistID) 
        ON DELETE NO ACTION ON UPDATE NO ACTION, 
     FOREIGN KEY (TrackID) REFERENCES Track (TrackID) 
        ON DELETE NO ACTION ON UPDATE NO ACTION 
    ); 




    CREATE TABLE Track 
(
    TrackID INTEGER PRIMARY KEY NOT NULL, 
    Name TEXT NOT NULL, 
    AlbumID INTEGER, 
    MediaTypeID INTEGER NOT NULL, 
    GenreID INTEGER, 
    Composer TEXT, 
    Millisecond INTEGER NOT NULL, 
    Byte INTEGER, 
    UnitPrice REAL NOT NULL, 
    FOREIGN KEY (AlbumID) REFERENCES Album (AlbumID) 
       ON DELETE NO ACTION ON UPDATE NO ACTION, 
    FOREIGN KEY (GenreID) REFERENCES Genre (GenreID) 
       ON DELETE NO ACTION ON UPDATE NO ACTION, 
    FOREIGN KEY (MediaTypeID) REFERENCES MediaType (MediaTypeID) 
       ON DELETE NO ACTION ON UPDATE NO ACTION 
); 

感謝。

Answer 1

それが属するクエリの最後にLIMIT句を配置してみてください。

SELECT 
    t.TrackID, t.Name, t.Millisecond 
FROM Track t 
INNER JOIN PlaylistTrack p 
    ON t.TrackID = p.TrackID 
WHERE p.Name = 'Background Music' 
ORDER BY t.Millisecond DESC 
LIMIT 10