[web2py] Selecting one Option of presorted database entries

[BlueShadow]

Hi I got a table called Articles which contain the nuber of views and the 
date when they where written. I Sorted them in the default.py by the views 
and by the date. I Show them Sorted by Date on my index page. Now I like to 
add a button to switch from the one to the other.
By default it should be ordered by date.
I got no Idea how I can achieve this can anyone help?