diff --git a/src/Models/Beleg.php b/src/Models/Beleg.php
index 214fe62..cbc8973 100644
--- a/src/Models/Beleg.php
+++ b/src/Models/Beleg.php
@@ -19,11 +19,11 @@ class Beleg
             $params = array_merge($params, [$s, $s, $s, $s]);
         }
         if (!empty($filter['year'])) {
-            $where[] = 'YEAR(b.beleg_datum) = ?';
+            $where[] = '(YEAR(b.beleg_datum) = ? OR b.beleg_datum IS NULL)';
             $params[] = (int)$filter['year'];
         }
         if (!empty($filter['month'])) {
-            $where[] = 'MONTH(b.beleg_datum) = ?';
+            $where[] = '(MONTH(b.beleg_datum) = ? OR b.beleg_datum IS NULL)';
             $params[] = (int)$filter['month'];
         }
         if (isset($filter['booked']) && $filter['booked'] !== '') {