In case the column is not found.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@10074 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/query.rb

@@ -902,7 +902,7 @@ class Query < ActiveRecord::Base
       end
       order_options.scan(/cf_\d+/).uniq.each do |name|
         column = available_columns.detect {|c| c.name.to_s == name}
-        join = column.custom_field.join_for_order_statement
+        join = column && column.custom_field.join_for_order_statement
         if join
           joins << join
         end