加入第三个表在MYSQL

Question

我有我需要加入三个表，我已经能够加入他们两个这样的：

SELECT 
    coll.title AS CollectionTitle, 
    cont.CollectionID, 
    cont.title AS ContainerTitle, 
    cont.ID as ContainerID, 
    cont.LevelContainerID 
FROM tblCollections_Content cont 
JOIN tblCollections_Collections coll 
    ON cont.collectionid = coll.id 
WHERE cont.title is NOT NULL 
ORDER BY CollectionID, ContainerID 

不过，我需要加入这个表以及tblCollections_UserFields，并需要这些来选择这些字段：ContentID, Title, Value, EADElementID;并在此处加入此表中的ContentID：cont.collectionid=coll.id（这是前两个表连接的位置）。

Answer 1

SELECT 
    coll.title AS CollectionTitle, 
    cont.CollectionID, 
    cont.title AS ContainerTitle, 
    cont.ID as ContainerID, 
    cont.LevelContainerID, 
    cont.ContentID, 
    user.Title, 
    user.Value, 
    user.EADElementID 
FROM tblCollections_Content cont 
JOIN tblCollections_Collections coll 
    ON cont.collectionid = coll.id 
JOIN tblCollections_UserFields user 
    ON cont.ContentId = user.ContentId 
WHERE cont.title is NOT NULL 
ORDER BY CollectionID, ContainerID 

我必须假设你在tblCollections_Content加入到你的tblCollections_UserFields具有内容识别列，您指定的列都在tblCollections_UserFields表。

根据这些表的参照完整性，您可能需要使用外连接来查看所有行。

Answer 2

只需添加JOIN anotherTable ON ...