Symfony 2：knppaginator 不允许左连接

Question

我使用 knppaginator 来获取分页结果。当我在查询中使用 LEFT JOIN 语句时，出现以下错误：

Cannot count query which selects two FROM components, cannot make distinction

我的控制器中的代码如下所示：

 public function paginationAction()
    {
        $em    = $this->get('doctrine.orm.entity_manager');

        $dql   = "SELECT p.name, c.name
                  FROM MyBundle:Products p
                  LEFT JOIN MyBundle:Categories c
                  WITH c.id = p.categoryId";

        $query = $em->createQuery($dql);

        $request = $this->getRequest();
        $paginator = $this->get('knp_paginator');
        $pagination = $paginator->paginate(
            $query,
            $request->query->getInt('page', 1),
            10
        );
        $viewData['pagination'] = $pagination;

        return $this->render('MyBundle:results.html.twig', $viewData);
    }

如何使 LEFT JOIN 语句起作用？当我省略 LEFT JOIN 时，一切正常。

Answer 1

这个问题之前被问过。看看这个答案：Doctrine : Pagination with left Joins