additional conditions on join in django

Question

Is it possible to add an additional condition to join statement created by django ORM?

What I need in SQL is

'SELECT "post"."id", COUNT("watchlist"."id") FROM "post" 
 LEFT OUTER JOIN "watchlist" 
    ON ("post"."id" = "watchlist"."post_id" AND "watchlist"."user_id" = 1) 
 WHERE "post"."id" = 123  GROUP BY …

In django most of this is

Post.objects.annotate(Count('watchinglist')).get(pk=123)

But how can I add AND "watchlist"."user_id" = … into JOIN condition with dhango ORM?

Adding it to filter fails to get Post objects with no associated objects in watchlist.

Answer 1

Post.objects.annotate(Count('watchinglist')).filter(pk=123).extra(where=['"watchlist"."user_id" = 1'])

Happy Coding.

Answer 2

I found a similar question here: http://stackoverflow.com/questions/256325/django-filtering-on-related-objects

And, looks like there's no way to do it without custom SQL.