Symfony3 -在控制器中创建两个表的连接查询

// src/AppBundle/Entity/User.php
namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="users")
 */
class User
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * @ORM\Column(type="integer")
     */
    private $id;

    /**
     * @ORM\Column(type="string")
     */
    private $name;

    // ...

    /**
     * @ORM\OneToMany(targetEntity="AppBundle\Entity\Order", mappedBy="user")
     */
    private $orders;

    // ...
}

// src/AppBundle/Entity/Order.php
namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="orders")
 */
class Order
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * @ORM\Column(type="integer")
     */
    private $id;

    /**
     * @ORM\Column(type="string")
     */
    private $product;

    // ...

    /**
     * @ORM\ManyToOne(targetEntity="AppBundle\Entity\User", inversedBy="orders")
     * @ORM\JoinColumn(name="user_id", referencedColumnName="id")
     */
    private $user;

    // ...
}

// src/AppBundle/Controller/DefaultController.php
namespace AppBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;

class DefaultController extends Controller
{
    public function indexAction()
    {
        $em = $this->getDoctrine()->getManager();

        $query = $em->createQueryBuilder()
            ->select('u', 'o')
            ->from('AppBundle:User', 'u')
            ->join('u.orders', 'o')
            ->getQuery();

        $result = $query->getResult();

        // 处理查询结果...

        return $this->render('default/index.html.twig', [
            'result' => $result,
        ]);
    }
}