diff --git a/application/controllers/api/frontend/v1/stv/Students.php b/application/controllers/api/frontend/v1/stv/Students.php
index b5ad79cf0..db546288c 100644
--- a/application/controllers/api/frontend/v1/stv/Students.php
+++ b/application/controllers/api/frontend/v1/stv/Students.php
@@ -894,7 +894,7 @@ class Students extends FHCAPI_Controller
 					n.start,
 					n.ende
 				  FROM public.tbl_notizzuordnung AS nz
-					JOIN public.tbl_notiz AS n ON nz.notiz_id = n.notiz_id
+					JOIN public.tbl_notiz AS n ON nz.notiz_id = n.notiz_id AND nz.prestudent_id IS NOT NULL
 					JOIN public.tbl_notiz_typ AS nt ON n.typ = nt.typ_kurzbz "
 				. $whereTags .
 				"