Symfony2 原则错误：无法对使用 HAVING 子句的查询进行计数。使用输出步行器进行分页

Question

我正在尝试获取非空集合，即至少有 1 个对象。集合实体与对象实体具有一对多关系。我正在使用 KNP 分页器对结果进行分页。这是我的职能：

  public function fetchAction(Request $request){
    $em = $this->getDoctrine()->getManager();

    $page = $request->get('page', 1);
    $limit = 10;

    $collections = $em->createQueryBuilder()
        ->select('c')
        ->add('from', 'CollectionBundle:Collection c LEFT JOIN c.object o')
        ->having('COUNT(o.id)>0')
        ->orderBy('c.date', 'DESC')
        ->getQuery();

    $collections = $this->get("knp_paginator")->paginate($collections, $page, $limit);

    return $this->render('CollectionBundle:Collection:fetch.html.twig', [
        'collections' => $collections
    ]);
}

错误

我不断收到以下错误

 Cannot count query that uses a HAVING clause. Use the output walkers for pagination

没有“Having”子句一切正常，但我必须获得非空集合。

Answer 1

wrap-queries 解决了这个问题

 $collections = $this->get("knp_paginator")->paginate($collections, $page, $limit,array('wrap-queries'=>true));

Answer 2

您可以实施手动计数，如文档中此处所述。

例如，您可以按如下方式修改代码：

$count = $em->createQueryBuilder()
        ->select('COUNT(c)')
        ->add('from', 'CollectionBundle:Collection c LEFT JOIN c.object o')
        ->having('COUNT(o.id)>0')
        ->orderBy('c.date', 'DESC')
        getSingleScalarResult();


    $collections = $em->createQueryBuilder()
        ->select('c')
        ->add('from', 'CollectionBundle:Collection c LEFT JOIN c.object o')
        ->having('COUNT(o.id)>0')
        ->orderBy('c.date', 'DESC')
        ->getQuery();

    $collections->setHint('knp_paginator.count', $count); 

    $collections = $this->get("knp_paginator")->paginate($collections, $page, $limit,array('distinct' => false));

    return $this->render('CollectionBundle:Collection:fetch.html.twig', [
        'collections' => $collections
    ]);

希望这有帮助

Answer 3

我的解决方案基于@Matteo的解决方案，因为我的查询有点复杂，我也想分享我的版本：

$qb = $this->createQueryBuilder('c');
    $qb->select('count(c.id)')
        ->addSelect('COUNT(DISTINCT m.id) AS HIDDEN messageCount')
        ->addSelect('COUNT(DISTINCT f.id) AS HIDDEN fileCount')
        ->join('c.user', 'u')
        ->join('c.status', 's')
        ->join('c.company', 'comp')
        ->leftJoin('c.files', 'f')
        ->leftJoin('c.messages', 'm');

    $this->_set_filters($filter, $qb);
    $qb->groupBy('c.id');
    $countQuery = $qb->getQuery();

    /** wrap query with SELECT COUNT(*) FROM ($sql)
    * I don't know what exactly does this block but
    * I coppied it from Doctrine\ORM\Tools\Pagination\Paginator::getCountQuery()
     */
    $platform = $this->getEntityManager()->getConnection()->getDatabasePlatform();
    $rsm = new Query\ResultSetMapping();
    $rsm->addScalarResult($platform->getSQLResultCasing('dctrn_count'), 'count');
    $countQuery->setHint(Query::HINT_CUSTOM_OUTPUT_WALKER, CountOutputWalker::class);
    $countQuery->setResultSetMapping($rsm);

    return $countQuery->getSingleScalarResult(); //returns integer

Answer 4

对于那些登陆此页面并询问在哪里可以找到选项的人，您可以在此处查看基本组件文档：

https://github.com/KnpLabs/knp-components/blob/master/docs/pager/config。 md