diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 3ed5562..5d0a2ae 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -547,7 +547,7 @@
 	{
 		if ($key === NULL OR $values === NULL)
 		{
-			return;
+			return $this;
 		}
 
 		$type = $this->_group_get_type($type);