Django GROUP BY Field Value

Question

Surprisingly, I could not find a way to make the group on request.

I have a set of queries qs, and I'm trying to group by some_prop.val, given that it qsexcludes entries where some_propthere are None.

Let's say that the values [1, 2, 3], then I would get the following result:

{1: entries1, 2: entries2, 3: entries3}

Does Django ORM provide any function for grouping such results?

Answer 1

There is no specific Django ORM path (as far as I know), but you can do the following to get a dictionary of entries grouped by field values:

• .values_list() flat=True, ( " ). .distinct() , :

  value_list = MyModel.objects.values_list(
      'interesting_field', flat=True
  ).distinct()
  

• value_list :

  group_by_value = {}
  for value in value_list:
      group_by_value[value] = MyModel.objects.filter(interesting_field=value)
  

group_by_value interesting_field , MyModel interesting_field=a value from value_list.

---

---

.

Q & a style, COUNT ... GROUP BY SQL.

.order_by .annotate(), .values().

:

COUNT ... GROUP BY SQL- Django ORM annotate(), values(), order_by() django.db.models Count :

:

class Books(models.Model):
    title  = models.CharField()
    author = models.CharField()

, , :

result = Books.objects.values('author')
                      .order_by('author')
                      .annotate(count=Count('author'))

: author count:

  author    | count
------------|-------  
 OneAuthor  |   5 
OtherAuthor |   2    
   ...      |  ...