diff --git a/lib/redmine/helpers/gantt.rb b/lib/redmine/helpers/gantt.rb
index 16f180090..206cdea24 100644
--- a/lib/redmine/helpers/gantt.rb
+++ b/lib/redmine/helpers/gantt.rb
@@ -151,7 +151,7 @@ module Redmine
       def issues
         @issues ||= @query.issues(
           :include => [:assigned_to, :tracker, :priority, :category, :fixed_version],
-          :order => "#{Project.table_name}.lft ASC, #{Issue.table_name}.id ASC",
+          :order => ["#{Project.table_name}.lft ASC", "#{Issue.table_name}.id ASC"],
           :limit => @max_rows
         )
       end