django: sort table data according to other table data

I have read the (excellent) documentation but I can't figure out how to do this.

I have a table which represents user friendships called "Shortlist" (with fields "from_user" and "to_user": both Foreign Keys to the classic auth_user table. Namely, from_user befriends to_user).

I have another table into which I log user events/actions (UserLog). In this table there are many fields including a "timestamp" and of course a "user" field (a foreign key to the auth_user table)

how can I retrieve data from table "Shortlist" for a specific user (from_user) ordered by the timestamp in UserLog table? Or how can I retrieve Shortlist data for a specific from_user ordered by the total number of "to_user" actions logged?

in other words I would like to retrieve all user's friends that are most active or order them by most recent action first.

thanks for your answer, however I think I might need some more help.开发者_如何学运维 What I want to do is to order users according to their activity (most active user first). Activities are logged in another table.

for instance I want to do something like this (if possible)

select * from Users U, (select count (id) from UserLog L where U.id=L.user_id) as actions order by actions desc

I would also like to sort them according to their latest actions (user whith most recent action, first)

any ideas (or best practices) on how to do those things?

Orderring by another table is possible with related field syntax:

Example:

UserProfile.objects.all().order_by('user__username')

To calculate thing based on fields use annotations