Question

I have two models: PostType1, PostType1.

class PostType1(models.Model):
    ...
    created_date = models.DateTimeField(_('created date'), blank=True, null=True)

class PostType2(models.Model):
    ...
    publish_date = models.DateTimeField(_('publish date'), blank=True, null=True)

I make a query for both getting:

posts_type1 = PostType1.objects.all()
posts_type2 = PostType2.objects.all()

I know how to chain them:

posts = chain(posts_type1,posts_type2)

I’m looking for a way to sort them by date descending.
Is this possible ? Or shall I look to raw sql?

Answer 1

So, if your plan is to sort the union of the two querysets, you have to use the sorted method. I would go for something like:

sorted(chain(posts_type1, posts_type2), 
       key=lambda x: x.created_date if isinstance(x, PostType1) 
                                    else x.publish_date)