[web2py] Selecting Latest Thread for a specific category

[Andrew]

In some forum code, I am trying to select the latest thread specific
to a forum category. But I am unsure how to do this

Any ideas are greatly appreciated

This is the code I tried with

{{last_posts = db(db.forum_post.category ==
db.category.id).select(db.forum_post.ALL, orderby=~db.forum_post.id,
limitby=(0,1))}}