I'm new to Django and still having some problems about simple queries.

Let's assume that I'm writting an email application. This is the Mail
model:

```

class Mail(models.Model):
    to = models.ForeignKey(User, related_name = "to")
    sender = models.ForeignKey(User, related_name = "sender")
    subject = models.CharField()
    conversation_id = models.IntegerField()
    read = models.BooleanField()
    message = models.TextField()
    sent_time = models.DateTimeField(auto_now_add = True)

```

Each mail has conversation\_id which identifies a set of email messages
which are written and replyed. Now, for listing emails in inbox, I
would like as gmail to show only last email per conversation.

I have the SQL equivalent which does the job, but how to construct native Django query for this?

```

select
        *
from
        main_intermail
where
        id in
        (select
                max(id)
        from
                main_intermail
        group by conversation_id); 

```

Thank you in advance!