symfony - Symfony2 form choice field -

i have product , category entity.

category entity adjacency list/materialized-path model.

product has relation category has relation product

in producttype class selectmenu categories @ specific level grouped parent name.

$builder->add('category', 'entity', array(             'label'    => 'category',             'class'    => 'test\adminbundle\entity\category',             'property' => 'name',             'group_by' => 'parentname',             'query_builder' => function(\doctrine\orm\entityrepository $er) {                  $qb = $er->createquerybuilder('c');                  return $qb->where($qb->expr()->like('c.path', ':path'))                         ->orderby('c.path', 'asc')                         ->setparameter('path', '%/%/%');             },     )); 

category got getparentname method:

public function getparentname() {     if (null === $this->getparent()) {     return null;     }      return $this->getparent()->getname(); } 

it works expected query executed every parent (a lot). if make join parent parent selectable in selectmenu don't want.

how limit queries?

or filter joined result?

i not fetchjoining... adding select querybuilder made work:

$qb = $er->createquerybuilder('c');  return $qb->select('c, p') ->leftjoin('c.parent', 'p') ->where($qb->expr()->like('c.path', ':path')) ->orderby('c.path', 'asc') ->setparameter('path', '%/%/%');