Symfony2 Doctrine Query, only populate single field in OneToMany Relationship - symfony

Question

Is it possible to only populate a single field in a QueryBuilder query that fetches the relationship, my case:
$query = $em->createQuery(
'SELECT s FROM IREnterpriseAppBundle:StockItem s
WHERE s.user = :currentUser AND s.deleted = 0
ORDER BY s.id DESC'
)->setParameters(array('currentUser' => $user));
Now the entity StockItem has a relationship to the user:
/**
* StockItem
*
* #ORM\Table()
* #ORM\Entity(repositoryClass="IREnterprise\AppBundle\Entity\StockItemRepository")
* #ORM\HasLifecycleCallbacks
*
* #ExclusionPolicy("all")
*
*/
class StockItem
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
* #Expose
*/
private $id;
/**
* #ORM\ManyToOne(targetEntity="IREnterprise\UserBundle\Entity\User", inversedBy="stockItems")
* #ORM\JoinColumn(name="user_id", referencedColumnName="id")
* #Expose
**/
private $user;
}
On the aforementioned query, the entire User object is fetched alongside with the stockitem, is it possible to only fetch/set a single field on the user object?
Since i am having issues excluding the rest of the user object with #exclusion policy: JMSSerializerbundle #expose relationship, ignores other entities policies
As a last resort i have to unset the fields of the user object in code, but that just seems retarded.

Answer 1

It is possible to only fetch a single field from a related entity but doing so, you won't be able to persist any change to the result.
If that's ok with you, you should use a JOIN and specify which fields from the related entity you want to fetch.
As mentioned in another answer, you can use createQueryBuilder instead of createQuery.
createQueryBuilder code sample:
$result = $em->getRepository('IREnterpriseAppBundle:StockItem')
->createQueryBuilder('s')
->select('s.id, u.id as user_id')
->join('s.user', 'u')
->where('s.user = :currentUser')
->andWhere('s.deleted = 0')
->setParameter('currentUser', $user)
->getQuery()
->getResult();
createQuery code sample:
$query = $em->createQuery(
'SELECT s.id, u.id as user_id FROM IREnterpriseAppBundle:StockItem s
JOIN s.user u
WHERE s.user = :currentUser AND s.deleted = 0
ORDER BY s.id DESC'
)->setParameters(array('currentUser' => $user));