title: Annotation with a subquery with multiple result in Django
body: <p>I use postgresql database in my project and I use below example from django <a href="https://docs.djangoproject.com/en/3.0/ref/models/expressions/#subquery-expressions" rel="nofollow noreferrer">documentation</a>.</p>
  
  <pre><code>from django.db.models import OuterRef, Subquery
  newest = Comment.objects.filter(post=OuterRef('pk')).order_by('-created_at')
  Post.objects.annotate(newest_commenter_email=Subquery(newest.values('email')[:1]))
  </code></pre>
  
  <p>but instead of newest commenter email, i need last two commenters emails. i changed <code>[:1]</code> to <code>[:2]</code> but this exception raised: <code>ProgrammingError: more than one row returned by a subquery used as an expression</code>.</p>