Fixed: Error when 'Display name' not set

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- Error when 'Display name' not set
 
 ## [4.0.1] - 2018-08-11
 ### Fixed

lib/Query/QueryProvider.php

@@ -92,7 +92,7 @@ class QueryProvider implements \ArrayAccess
             (empty($gAdmin) ? "false" : $gAdmin) . " AS admin";
         $userColumns
             = "$uUID AS uid, " .
-            (empty($uName) ? "null" : $uName) . " AS name, " .
+            (empty($uName) ? $uUID : $uName) . " AS name, " .
             (empty($uEmail) ? "null" : $uEmail) . " AS email, " .
             (empty($uQuota) ? "null" : $uQuota) . " AS quota, " .
             (empty($uHome) ? "null" : $uHome) . " AS home, " .