How to Perform Left Joins in Doctrine: A Guide with Code Examples-PHP Tutorial-php.cn

How to Perform Left Joins in Doctrine: A Guide with Code Examples

Mary-Kate Olsen

Release： 2024-10-30 05:02:02

Original

440 people have browsed it

How to Perform Left Joins in Doctrine: A Guide with Code Examples

Performing Left Joins in Doctrine

Doctrine provides comprehensive capabilities for creating and executing SQL queries, including the ability to perform left joins. This article demonstrates how to perform left joins using Doctrine, addressing the pain points you might encounter in your code.

Left Join Syntax

When utilizing associations between entities, the syntax for left joins is straightforward:

<code class="php">public function getHistory($users) {
    $qb = $this->entityManager->createQueryBuilder();
    $qb
        ->select('a', 'u')
        ->from('Credit\Entity\UserCreditHistory', 'a')
        ->leftJoin('a.user', 'u')
        ->where('u = :user')
        ->setParameter('user', $users)
        ->orderBy('a.created_at', 'DESC');

    return $qb->getQuery()->getResult();
}</code>

Copy after login

In this example, a condition is applied to the joined result, making it irrelevant whether a left join or simply a join is used.

Left Join Without Associations

If no associations are available, the left join query resembles the following:

<code class="php">public function getHistory($users) {
    $qb = $this->entityManager->createQueryBuilder();
    $qb
        ->select('a', 'u')
        ->from('Credit\Entity\UserCreditHistory', 'a')
        ->leftJoin(
            'User\Entity\User',
            'u',
            \Doctrine\ORM\Query\Expr\Join::WITH,
            'a.user = u.id'
        )
        ->where('u = :user')
        ->setParameter('user', $users)
        ->orderBy('a.created_at', 'DESC');

    return $qb->getQuery()->getResult();
}</code>

Copy after login

This query results in an array similar to the following:

<code class="php">array(
    array(
        0 => UserCreditHistory instance,
        1 => Userinstance,
    ),
    array(
        0 => UserCreditHistory instance,
        1 => Userinstance,
    ),
    // ...
)</code>

Copy after login

The above is the detailed content of How to Perform Left Joins in Doctrine: A Guide with Code Examples. For more information, please follow other related articles on the PHP Chinese website!