diff --git a/src/Search.php b/src/Search.php
index 915561f3dcb..1c936dc0ad2 100644
--- a/src/Search.php
+++ b/src/Search.php
@@ -1024,7 +1024,7 @@ public static function constructSQL(array &$data)
                     if ($first) {
                         $first = false;
                     } else {
-                        $QUERY .= " UNION ";
+                        $QUERY .= " UNION ALL ";
                     }
                     $tmpquery = "";
                    // AllAssets case