Question

我正在尝试使用子查询插入数据。我只会在下面发布我的SELECT声明。

SELECT PlaylistCode
FROM Playlists
WHERE Name_Of_Playlist = 'X'
AND 
(SELECT Code
  FROM Songs
  INNER JOIN Artists ON Artists.PageURL = Songs.PageURL
  WHERE Artist = 'X'
  LIMIT 200)

错误代码：1242。子查询返回的行多于0.016秒

Answer 1

尝试以下查询

SELECT PlaylistCode
FROM Playlists
WHERE exits 
(SELECT Code
  FROM Songs
  INNER JOIN Artists ON Artists.PageURL = Songs.PageURL
  WHERE Artist = 'X'
  LIMIT 200) and Name_Of_Playlist = 'X'

Answer 2

根据您的要求，您需要先使用select case然后使用join相应的表

  INSERT INTO Playlists (PlaylistCode)
    SELECT CASE WHEN a.Artist = 'X' THEN 'X' ELSE s.Code END   
    FROM Songs s
    INNER JOIN Artists a ON a.PageURL = s.PageURL

使用子查询将数据插入表中

2 个答案: