problem ordering by votes with django-voting

Question

I have a model Post, and a model Vote. Vote (form django-voting) is essentially just a pointer to a Post and -1, 0, or 1.

There is also Tourn, which is a start date and an end date. A Post made between the start and end of a Tourn is submitted to that tournament.

For the sake of rep calculation, I'm trying to find the top 3 winners of a tournament. This is what I have:

    posts = Post.objects.filter(status=2, created_at__range=(tourn.start_date, tourn.end_date))

    start = tourn.start_date - timedelta(days=1)
    end = tourn.end_date + timedelta(days=1)
    qn = connection.ops.quote_name
    ctype = ContentType.objects.get_for_model(Post)

    posts.extra(select={'score': """
            SELECT SUM(vote)
            FROM %s
            WHERE content_type_id = %s
            AND object_id = %s.id
            AND voted_at > DATE(%s)
            AND voted_at < DATE(%s)
        """ % (qn(Vote._meta.db_table), ctype.id, qn(Post._meta.db_table), start, end)},
                order_by=['-score'])

    if tourn.limit_to_category:
        posts.filter(category=tourn.category)

    if len(posts) >= 1:
        tourn_winners_1.append(posts[0].author)
        resp += " 1: " + posts[0].author.username + "\n"

    if len(posts) >= 2:
        tourn_winners_2.append(posts[1].author)
        resp += " 2: " + posts[1].author.username + "\n"

    if len(posts) >= 3:
        tourn_winners_3.append(posts[2].author)
        resp += " 3: " + posts[2].author.username + "\n"

It seems simple enough, but for some reason the results are wrong.

The query that gets made is thus:

SELECT "blog_post"."id", "blog_post"."title", "blog_post"."slug", "blog_post"."a
uthor_id", "blog_post"."creator_ip", "blog_post"."body", "blog_post"."tease", "b
log_post"."status", "blog_post"."allow_comments", "blog_post"."publish", "blog_p
ost"."created_at", "blog_post"."updated_at", "blog_post"."markup", "blog_post"."
tags", "blog_post"."category_id" FROM "blog_post" WHERE ("blog_post"."status" =
2  AND "blog_post"."created_at" BETWEEN 2008-12-21 00:00:00 and 2009-01-04 00:00
:00) ORDER BY "blog_post"."publish" DESC

It seems that posts.extra() isn't getting applied to the query at all...

Answer 1

I think you need to assign posts to the return value of posts.extra():

posts = posts.extra(select={'score': """
                    SELECT SUM(vote)
                    FROM %s
                    WHERE content_type_id = %s
                    AND object_id = %s.id
                    AND voted_at > DATE(%s)
                    AND voted_at < DATE(%s)
                """ % (qn(Vote._meta.db_table), ctype.id, qn(Post._meta.db_table), start, end)},
                        order_by=['-score'])