diff --git a/src/AppBundle/Repository/Rebrickable/ThemeRepository.php b/src/AppBundle/Repository/Rebrickable/ThemeRepository.php
index 11b0d88..8752161 100644
--- a/src/AppBundle/Repository/Rebrickable/ThemeRepository.php
+++ b/src/AppBundle/Repository/Rebrickable/ThemeRepository.php
@@ -2,8 +2,21 @@
 
 namespace AppBundle\Repository\Rebrickable;
 
+use AppBundle\Entity\Rebrickable\Theme;
 use AppBundle\Repository\BaseRepository;
+use Doctrine\ORM\Query\Expr\Join;
 
 class ThemeRepository extends BaseRepository
 {
+    public function findAllSubthemes(Theme $theme) {
+
+        $subQueryBuilder =  $this->createQueryBuilder('subtheme');
+
+        $queryBuilder = $this->createQueryBuilder('subtheme')
+            ->leftJoin(Theme::class,'theme', Join::WITH, 'subtheme.parent = theme.id')
+            ->where('subtheme.parent = :id')
+            ->setParameter('id', $theme->getId());
+
+        return $queryBuilder->getQuery()->getResult();
+    }
 }