diff --git a/model/DataQuery.php b/model/DataQuery.php
index cea43dd26..25a44f4ab 100644
--- a/model/DataQuery.php
+++ b/model/DataQuery.php
@@ -514,7 +514,6 @@ class DataQuery {
 	public function subtract(DataQuery $subtractQuery, $field='ID') {
 		$subSelect= $subtractQuery->getFinalisedQuery();
 		$subSelect->select($this->expressionForField($field, $subSelect));
-		$this->ensureSelectContainsOrderbyColumns($subSelect);
 		$this->where($this->expressionForField($field, $this).' NOT IN ('.$subSelect->sql().')');
 	}