How to insert Django SELECT?

Question

class Friendship(models.Model):
    from_friend = models.ForeignKey(User, related_name='friend_set')
    to_friend = models.ForeignKey(User, related_name='to_friend_set')

I would like to select all to_friends that have from_friend = specific user.

Then, I would like to pass to_friends for the internal filter to another .objects.filter (). Is this a way to do this?

Thanks!

Answer 1

As pccardune says, you get the appropriate users as follows:

friendships = Friendship.objects.filter(from_friend=some_user)

But in fact, you can pass this directly to your next request:

second_select = Whatever.objects.filter(friend__in=friendships)

Answer 2

I would like SELECTall to_friendsfor which from_friend= a specific User.

You can get all Friendship objects for this step like this:

friendships = Friendship.objects.filter(from_friend=some_user)

to_friend , values_list :

friends = friendships.values_list("to_friend", flat=True)

friends - ValuesListQuery, , . filter().

Answer 3

This seems to return the desired results.

User.objects.filter(to_friend_set__from_friend=1)