在doctrine（已加入）类表继承中查询根实体的字段

Question

I have a entity named Content. This is my abstract base class for all my other Content related entities.

/**
* MyBundle\Entity\Content
*
* @ORM\Entity(repositoryClass="MyBundle\Repository\ContentRepository")
* @ORM\InheritanceType("JOINED")
* @ORM\DiscriminatorColumn(name="discr", type="string")
* @ORM\Table(name="MyBundle_content")
* @ORM\HasLifecycleCallbacks
*/
abstract class Content

Content properties:

• id
• updated
• ....

Further I have a lot of different entities that all extend Content.

In my repository (of another entity that's not Content and not extending Content) I have a rather complex query where i want to select the "updated" field of all content objects (depending on some other unrelevant stuff)

Edit: But the Content entity is joined onto another entity with "->leftJoin('p.content', 'c')" in that query. What I mean is that I'm in the Repository of a completely different Entity that just has a relation to Content, that's why I'm joining the content onto there with the '->leftJoin('p.content', 'c')' (Where p is the Entity in which Repository I'm currently in.

The problem is, that in that query doctrine is joining every single Entity that extends Content on to the content table. Because I have quite a lot of entities the error I get is

General error: 1116 Too many tables; MySQL can only use 61 tables in a join

In my case I don't need all these joined tables because the info I need is in the Content table alone.

Is there any way to only query the root entity table while still using the querybuilder and not writing my own sql?

Answer 1

In the end I wrote the whole SQL Statement myself, because while joining multiple entities there is no way just to join their base entity, instead of the actual inheriting class.

Edit: Talked to a developer of doctrine, writing the SQL statement yourself is the way to go.