symfony错误:预期=，<，<=，<>，>，>=，!=，got‘’

Question

我有一个查询，它查找从控制器中的变量获得的结果。

$category = $request->request->get('category');

$catContent = $em->getRepository('PublicartelAppBundle:Content')->findByCategory($category);

public function findByCategory($category)
    {
        $em = $this->getEntityManager();

        $dql = 'SELECT c FROM Publicartel\AppBundle\Entity\Content c';

        if (!is_null($category)) {
            $dql .= " WHERE c.categories.name = category";
        }

        $query = $this->getEntityManager()
            ->createQuery($dql)
            ->setHydrationMode(\Doctrine\ORM\Query::HYDRATE_ARRAY);

        if (!is_null($category)) {
            $query->setParameter('category', $category);
        }

        return $query->getResult();
    }

但是，当我对查询运行操作时，出现了以下错误：

[Syntax Error] line 0, col 71: Error: Expected =, <, <=, <>, >, >=, !=, got '.'

从Publicartel\AppBundle\Entity\Content c中选择c，其中c.categories.name =类别

$categories是实体内容的属性。

class Content
{
private $categories;

    public function __construct()
    {
        $this->categories = new \Doctrine\Common\Collections\ArrayCollection();
    }

public function addCategories(\Publicartel\AppBundle\Entity\Category $categories)
    {
        $this->categories[] = $categories;

        return $this;
    }

    public function removeCategories(\Publicartel\AppBundle\Entity\Category $categories)
    {
        $this->categories->removeElement($categories);
    }

    public function setCategories(\Publicartel\AppBundle\Entity\Category $categories = null)
    {
        $this->categories = $categories;

        return $this;
    }
    public function getCategories()
    {
        return $this->categories;
    }
}

奇怪的是，当我获取变量时，错误并没有出现。

$category = $request->query->get('category');

Answer 1

不能以这种方式参照子对象：

SELECT c FROM Publicartel\AppBundle\Entity\Content c WHERE c.categories.name = :category

您需要在此之前使用JOIN，并使用该连接实体的别名。如下所示：

SELECT c, cat FROM Publicartel\AppBundle\Entity\Content c JOIN c.categories cat WHERE cat.name = :category

现在，要么使用LEFT JOIN，要么只使用JOIN，它应该可以工作。