Symfony和Doctrine使连接的查询起作用

Question

我有一个SQL查询返回一个表(国家)中的所有行,这些表在另一个表(ducks)中有相关条目,但我很难将其转换为DQL.这是一个标准的一对多关系,因为每个国家可以有多个鸭子,我相信它都是正确设置的,因为我可以在一个国家内返回鸭子并使用标准代码返回该国家.

工作查询是:

SELECT c.* FROM country c 
INNER JOIN ducks d 
ON c.id = d.country_id 
GROUP BY c.country 
ORDER BY c.country ASC

我试过将其转换为:

SELECT c FROM WfukDuckBundle:Country c 
INNER JOIN WfukDuckBundle:Ducks d 
ON c.id = d.country_id 
GROUP BY c.country 
ORDER BY c.country ASC

这会产生以下错误:

[Semantical Error] line 0, col 79 near 'd ON': Error: Identification Variable 
WfukDuckBundle:Ducks used in join path expression but was not defined before. 

我对Symfony/Doctrine很新,所以我怀疑它可能是显而易见的!

我正在使用带有学说的Symfony 2.0.11

更新:我也尝试过:

SELECT c FROM WfukDuckBundle:Country c 
INNER JOIN c.ducks d 
ON c.id = d.country_id 
GROUP BY c.country 
ORDER BY c.country ASC

其中'ducks'在Country类中定义为:

/**
 * @ORM\OneToMany(targetEntity="Ducks", mappedBy="country")
 */
protected $ducks;

public function __construct()
{
    $this->ducks = new ArrayCollection();
}

ducks类中country的定义是:

/**
* @ORM\ManyToOne(targetEntity="Country", inversedBy="ducks")
* @ORM\JoinColumn(name="country_id", referencedColumnName="id")
*/
private $country;

Answer 1

帮自己一个忙,并使用查询构建器.更易于阅读,更新和重用您的查询

<?php

namespace Vendor\Prefix\Repository;

use Doctrine\ORM\EntityRepository;

class SomeRepository extends EntityRepository
{
    public function countryDucks()
    {
        // $em is the entity manager
        $qb = $em->createQueryBuilder();

        $qb
            ->select('country', 'duck')
            ->from('WfukDuckBundle:Country', 'country')
            ->innerJoin('country.ducks', 'duck')
            ->groupBy('country.country')
            ->orderBy('country.country', 'ASC')
        ;

        $query = $qb->getQuery();

        // Potential Hydration Modes
        // --------------------------------
        // Doctrine\ORM\Query::HYDRATE_OBJECT
        // Will give you an array of your object entities
        // --------------------------------
        // Doctrine\ORM\Query::HYDRATE_ARRAY 
        // Will give you an array mimicking 
        // your object graph 
        // --------------------------------

        return $query->getResult(\Doctrine\ORM\Query::HYDRATE_ARRAY);
    }
}