Question

我有一个名为Home的视图：

CREATE VIEW `skohr`.`Home` AS
Select Song_OID, Song_Name, Album_Name, Artist_First_Name, Artist_Last_Name, Band_Name, Genre, Album_Art_File_Path
From Song, Album, Artist, Track_Number, Made
Where Song_OID = Track_Number.Song_OID_FK AND Album_OID=Track_Number.Album_OID_FK AND Album_OID=Made.Album_OID_FK AND Artist_OID=Made.Artist_OID_FK
ORDER BY Song_Name Asc

我在视图上运行了以下查询以获取我想要的表：

Select DISTINCT * From Home LEFT OUTER JOIN (SELECT * FROM Song_Setting, user WHERE User_OID=User_OID_FK) AS UserSongs
ON Song_OID=Song_OID_FK

如何将两个单独的查询合并为一个以创建单个视图？

Answer 1

尝试创建视图

CREATE VIEW `skohr`.`MyNewView` AS

Select DISTINCT * From Home h
LEFT OUTER JOIN Song_Setting x
    ON h.Song_OID_FK = x.Song_OID
INNER JOIN user u
    ON u.User_OID = x.User_OID_FK

Answer 2

::对请求MySQL版本的评论的回复::

我今天没有专门使用MySQL，但是你有没有理由不像你的其他数据集一样使用子查询？像这样：

Select DISTINCT * From 
(
    Select Song_OID, Song_Name, Album_Name, Artist_First_Name, Artist_Last_Name, Band_Name, Genre, Album_Art_File_Path
    From Song, Album, Artist, Track_Number, Made
    Where Song_OID = Track_Number.Song_OID_FK AND Album_OID=Track_Number.Album_OID_FK AND Album_OID=Made.Album_OID_FK AND Artist_OID=Made.Artist_OID_FK
) as a
LEFT OUTER JOIN (SELECT * FROM Song_Setting, user WHERE User_OID=User_OID_FK) AS b
ON a.Song_OID=b.Song_OID_FK

如果这对MySQL不起作用，我想你可能会考虑使用临时/内存表。因此，请研究在MySQL中创建临时表，创建临时表并使用我在下面的CTE中捕获的子查询填充它，然后将其加入到您的其他查询中。

如果这是SQL Server，您可以使用CTEs

只需将以下代码放入View中即可获得所需内容。

WITH Home AS 
(
Select Song_OID, Song_Name, Album_Name, Artist_First_Name, Artist_Last_Name, Band_Name, Genre, Album_Art_File_Path
From Song, Album, Artist, Track_Number, Made
Where Song_OID = Track_Number.Song_OID_FK AND Album_OID=Track_Number.Album_OID_FK AND Album_OID=Made.Album_OID_FK AND Artist_OID=Made.Artist_OID_FK
)
Select DISTINCT * From Home 
LEFT OUTER JOIN (SELECT * FROM Song_Setting, user WHERE User_OID=User_OID_FK) AS UserSongs
ON Song_OID=Song_OID_FK

将SQL视图与左外部联接查询组合在一起

2 个答案: