diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 3f1a802..ab19d97 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -1553,7 +1553,7 @@
 
 		is_bool($escape) OR $escape = $this->_protect_identifiers;
 
-		$keys = array_keys($this->_object_to_array(current($key)));
+		$keys = array_keys($this->_object_to_array(reset($key)));
 		sort($keys);
 
 		foreach ($key as $row)