php - Doctrine2 QB OneToMany 连接上的语义错误

Question

我正在尝试使用 Doctrine2 QueryBuilder 创建查询。

    $qb = $this->getObjectManager()->createQueryBuilder();
    $qb->select( array('n', 't', 'c') )
        ->from('Application\Entity\Notification', 'n')
        ->leftJoin('n.notificationType', 't')
        ->leftJoin('n.course', 'c')
        ->leftJoin('c.studyCourses', 's');

实体类(class)中的相关代码如下所示:

    /**
     * @ORM\OneToMany(targetEntity="StudyCourses", mappedBy="Course", cascade={"all"})
     */
    protected $studyCourses;

实体StudyCourse中的相​​关代码如下所示:

    /**
     * @ORM\ManyToOne(targetEntity="Course", inversedBy="studyCourses")
     * @ORM\JoinColumn(name="Course", referencedColumnName="Id", nullable=true)
     */
    protected $course;  

现在，当我尝试运行查询时，我在“”附近遇到语义错误。我认为打印 Doctrine 创建的 SQL 可以为我提供有关此错误的更好信息，但事实上它是:

SELECT n0_.Id AS Id0, n0_.Timestamp AS Timestamp1, n0_.TitleHtml AS TitleHtml2, n0_.ContentHtml AS ContentHtml3, n1_.Id AS Id4, n1_.Created AS Created5, n1_.Updated AS Updated6, n1_.Name AS Name7, c2_.Id AS Id8, c2_.Created AS Created9, c2_.Updated AS Updated10, c2_.Name AS Name11, c2_.Description AS Description12, c2_.Code AS Code13, c2_.ObjectId AS ObjectId14, c2_.IsActive AS IsActive15, n0_.NotificationType AS NotificationType16, n0_.User AS User17, n0_.Department AS Department18, n0_.Study AS Study19, n0_.Course AS Course20, n0_.Category AS Category21, c2_.Language AS Language22 FROM Notification n0_ LEFT JOIN NotificationType n1_ ON n0_.NotificationType = n1_.Id LEFT JOIN Course c2_ ON n0_.Course = c2_.Id LEFT JOIN 

它在 LEFT JOIN 之后停止!

任何帮助将不胜感激，因为我真的不知道我做错了什么，也不知道如何解决这个问题。我在互联网上搜索了类似的错误，但到目前为止还没有运气。

Answer 1

尝试至少选择在 select 数组内的 StudyCourses 表中形成 leftJoin 所需的列。首先尝试获取诸如“select( array('n', 't', 'c', 's') )”之类的所有内容。有时，如果您未选择该列，它就会中断。如果这有效，不要获取 StudyCourses 表中的所有列，只需获取 select 中的相关列以形成 leftJoin，例如“s.id”。

希望这有帮助。

干杯!