diff --git a/modules/system/system.install b/modules/system/system.install
index 7fad4a2..eac4fba 100644
--- a/modules/system/system.install
+++ b/modules/system/system.install
@@ -2740,11 +2740,12 @@ function system_update_7061(&$sandbox) {
 
     // Delete stale rows from {upload} where the vid is not in the
     // {node_revisions} table.
-    $delete_node_subquery = db_select('node_revision', 'nr');
-    $delete_node_subquery->fields('nr', array('vid'));
-    $delete_node_subquery->where('nr.vid = ' . $upload_table_prefix . 'upload.vid');
     db_delete('upload')
-      ->notExists($delete_node_subquery)
+      ->notExists(
+        db_select('node_revision', 'nr')
+        ->fields('nr', array('vid'))
+        ->where('nr.vid = {upload}.vid')
+      )
       ->execute();
 
     // Retrieve a list of node revisions that have uploaded files attached.