php – Symfony2教义查询

select * from Post inner join Category on Post.category_id=Category.id inner join Priority on Post.priority_id=Priority.id order by priority_number desc

我使用了存储库类,其中写了一个函数

public function findAllOrderedByPriorityPost()
    {

        return $this->getEntityManager()
                ->createquery('select p,c,pr from RodasysfourmBundle:Post p inner join 
RodasysfourmBundle:Category c  inner join RodasysfourmBundle:Priority pr order by pr.priorityNumber desc')
                ->getResult();
    }

当我使用这个功能,我得到以下错误

[Semantical Error] line 0,col 85 near 'c inner join': Error: Identification Variable RodasysfourmBundle:Category used in join path expression but was not defined before.

哪个方法最好在自定义存储库中或作为服务使用此查询？

任何帮助赞赏.