diff --git a/lib/shop.lib.php b/lib/shop.lib.php
index dc5c300f7..1b057866d 100644
--- a/lib/shop.lib.php
+++ b/lib/shop.lib.php
@@ -282,7 +282,7 @@ class item_list
                 if ($this->ca_id3) {
                     $where_ca_id[] = " ca_id3 like '{$this->ca_id3}%' ";
                 }
-                $where[] = implode(" or ", $where_ca_id);
+                $where[] = " ( " . implode(" or ", $where_ca_id) . " ) ";
             }
 
             if ($this->order_by) {