diff --git a/typo3/sysext/lowlevel/Classes/Database/QueryGenerator.php b/typo3/sysext/lowlevel/Classes/Database/QueryGenerator.php
index a516de6906840518634f2f4040452de2ef87b400..d49fa95a21bf44bace37e5c15d86958c9db2dd33 100644
--- a/typo3/sysext/lowlevel/Classes/Database/QueryGenerator.php
+++ b/typo3/sysext/lowlevel/Classes/Database/QueryGenerator.php
@@ -1340,7 +1340,7 @@ class QueryGenerator
 
                     foreach ($this->tableArray[$from_table] as $key => $val) {
                         $this->settings['labels_noprefix'] =
-                            $this->settings['labels_noprefix'] == 1
+                            ($this->settings['labels_noprefix'] ?? '') == 1
                                 ? 'on'
                                 : $this->settings['labels_noprefix'];
                         $prefixString =