You can use the go_order_desc and go_order_asc commands to sort a query in descending or ascending order for a specific field. To do so, you also have to specify the desired field accordingly with orderfield=Fieldname.
For example:
http://localhost/perl/avclient/index.pl? go_order_asc&orderfield=Date
When you use this command, the current selection is sorted in accordance with the 'Date' field.