SYNFONY - CREATEQUERYBUİLDER - CONCAT

$students = $em->createQueryBuilder()
            ->select("concat(pr.name,' ',pr.surname as student_name")///THİS IS CONCAT
            ->from('CoreCorporateBundle:Classroom','cr')
            ->innerJoin('cr.classroom_members','crm')
            ->innerJoin('crm.profile','pr')
            ->where('cr.uuid =:uuid')
            ->andwhere('crm.type =:type')
            ->setParameter('uuid',$classroom_uuid)
            ->setParameter('type','ogrenci')
            ->getQuery()
            ->getArrayResult();