在SQLite3中關聯外鍵

Question

我只是想創建一個新的播放列表，其中包含所有存儲的曲目中最長的10首歌曲。這裏是我的代碼和下面的架構，請解釋一下，請解釋我如何將播放列表和軌道的foriegn鍵關聯到PlaylistTrack？

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'; 

架構：

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

嘗試放置LIMIT條款在它所屬的查詢的末尾：

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