diff --git a/core/lib/Drupal/Core/Database/Driver/sqlite/Update.php b/core/lib/Drupal/Core/Database/Driver/sqlite/Update.php
index 38d8d5c..1426d0c 100644
--- a/core/lib/Drupal/Core/Database/Driver/sqlite/Update.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Update.php
@@ -39,7 +39,9 @@ class Update extends QueryUpdate {
           $this->removeFieldsInCondition($fields, $child_condition['field']);
         }
         else {
-          unset($fields[$child_condition['field']]);
+          if(isset($fields[$child_condition['field']])) {
+            unset($fields[$child_condition['field']]);
+          }
         }
       }
     }