How to query as GROUP BY in django

0 votes

Query a model:

Members.objects.all()

And it returns:

Eric, Salesman, X-Shop
Freddie, Manager, X2-Shop
Teddy, Salesman, X2-Shop
Sean, Manager, X2-Shop

What I want is to know the best Django way to fire a group_by query to my database, like:

Members.objects.all().group_by('designation')

Which doesn't work, of course. I know we can do some tricks on django/db/models/query.py, but I am just curious to know how to do it without patching.

Apr 23, 2020 in Python by kartik
• 37,510 points
5,757 views

1 answer to this question.

0 votes

Hii,

Django does not support free group by queries. I learned it in the very bad way. ORM is not designed to support stuff like what you want to do, without using custom SQL. You are limited to:

  • RAW sql (i.e. MyModel.objects.raw())
  • cr.execute sentences (and a hand-made parsing of the result).
  • .annotate() (the group by sentences are performed in the child model for .annotate(), in examples like aggregating lines_count=Count('lines'))).

Over a queryset qs you can call qs.query.group_by = ['field1', 'field2', ...] but it is risky if you don't know what query are you editing and have no guarantee that it will work and not break internals of the QuerySet object. 

Besides, it is an internal (undocumented) API you should not access directly without risking the code not being anymore compatible with future Django versions.

Hope this works!!

Thank You!!

answered Apr 23, 2020 by Niroj
• 82,880 points

Related Questions In Python

0 votes
1 answer

How to insert value by one post method in 2 table with Django?

try  import-export   library of Django or if you are ...READ MORE

answered Nov 12, 2020 in Python by Gitika
• 65,910 points
949 views
0 votes
1 answer

How to switch pages using Ajax in Django?

You should use django-pjax which is built exactly for ...READ MORE

answered Oct 9, 2018 in Python by aryya
• 7,450 points
1,292 views
0 votes
1 answer

How to get all related Django model objects in Python?

This actually gives you the property names ...READ MORE

answered Nov 14, 2018 in Python by Nymeria
• 3,560 points

edited Dec 18, 2018 by Nymeria 6,273 views
0 votes
1 answer

How to write to CSV line by line in python

The simple way of doing this will ...READ MORE

answered Nov 15, 2018 in Python by findingbugs
• 3,260 points
5,119 views
0 votes
2 answers
+1 vote
2 answers

how can i count the items in a list?

Syntax :            list. count(value) Code: colors = ['red', 'green', ...READ MORE

answered Jul 7, 2019 in Python by Neha
• 330 points

edited Jul 8, 2019 by Kalgi 4,023 views
0 votes
1 answer
0 votes
1 answer

How do I filter query objects by date range in Django?

Hello @kartik, Use Sample.objects.filter(date__range=["2020-01-01", "2020-01-31"]) Or if you are just ...READ MORE

answered Jun 26, 2020 in Python by Niroj
• 82,880 points
32,888 views
0 votes
1 answer

How to dynamically compose an OR query filter in Django?

Hello @kartik, You could chain your queries as ...READ MORE

answered Aug 3, 2020 in Python by Niroj
• 82,880 points
4,961 views
webinar REGISTER FOR FREE WEBINAR X
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP