Group By in django 1.8 - mysql

Question

I have the next structure in my django app:
class A(models.Model):
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=100)
time = models.DateTimeField(auto_now_add=True)
I want select the earliest time of each name, in database like:
╔═════╤══════╤════════════╗
║ id │ name │ time ║
╠═════╪══════╪════════════╣
║ 1 │ a │ 2018-09-10 ║
║ 2 │ a │ 2018-09-11 ║
║ 3 │ b │ 2018-09-10 ║
║ 4 │ b │ 2018-09-11 ║
╚═════╧══════╧════════════╝
Then the result should be:
╔═════╤══════╤════════════╗
║ id │ name │ time ║
╠═════╪══════╪════════════╣
║ 1 │ a │ 2018-09-10 ║
║ 3 │ b │ 2018-09-10 ║
╚═════╧══════╧════════════╝
I know raw-sql is a solution, but is it possible to use django query expressions? I'm using django 1.8.
Any help please.

Answer 1

We can do this with:
from django.db.models import Min
A.objects.values('name').annotate(
min_time=Min('time')
).order_by('name')
This will result in a QuerySet object that contains dictionaries: in this case it will look like:
<QuerySet [{'name': 'a', 'min_time': date(2018,09,10)},
{'name': 'b', 'min_time': date(2018,09,10)}]>
So you can iterate over the queryset, and thus process the dictionary elements.