Django ORM, group by day

Question

I am trying to group products by DAY, however date_created is a datetime field.

Product.objects.values('date_created') 
               .annotate(available=Count('available_quantity'))

returns:

[
    {'date_created': datetime.datetime(2012, 4, 14, 13, 3, 6), 'available': 1},
    {'date_created': datetime.datetime(2012, 4, 14, 17, 12, 9), 'available': 1},
    ...
]

I want:

[
    {'date_created': datetime.datetime(2012, 4, 14), 'available': 2}, ...
]

edit: database backend MYSQL

Asked By: Hedde van der Heide

||

Source

Answer 1

In Django 1.4, you could use .dates('date_created', 'day') instead of .values().

Try this code snippet:

Product.objects.annotate(available=Count('available_quantity')) 
  .dates('date_created', 'day')

This should return:

[
    {'date_created': datetime.datetime(2012, 4, 14), 'available': 2}, ...
]

Answered By: cfedermann

Answer 2

Inspired by this question try this for MySQL

from django.db.models import Count

Product.objects.extra(select={'day': 'date( date_created )'}).values('day') 
               .annotate(available=Count('date_created'))

Answered By: San4ez

Answer 3

Similar approach from San4ez‘s answer, but returning dates as ‘YYYY-MM-DD’ instead of ‘datetime.datetime(YYYY, MM, DD)’:

Product.objects.extra(select={'day': "TO_CHAR(date_created, 'YYYY-MM-DD')"})
               .values('day') 
               .order_by('day') 
               .annotate(available=Count('date_created'))

Answered By: Zanon

Answer 4

You can try

Product.objects.extra(select={'day': "TO_CHAR(date_created, 'YYYY-MM-DD')"})
                .values('day')
                .order_by('day')
                .annotate(bets=Count('date_created'))

Answered By: ronin

Answer 5

By following the answer of San4ez and the changes from Zanon

For me i had to make a workaround to work with Postgres or Sqlite, since the Count() function will consider the datetime field, doesn’t matter if you going to create a "day" input just with the date because the date_created is still holding the time information, so multiple records with time on it wont be merged and counted up, after trying many things deferents i reached that way of skipping the time

Django 2.2

from django.db.models import Count

# Change date() to to_char(created_at, 'YYYY-MM-DD') if using Postgres
Product.objects.extra(select={'day': 'date( date_created )'})
    .values('day') 
    .order_by('date_created__date')
    .annotate(available=Count('date_created__date'))

Answered By: Diego Vinícius

Django ORM, group by day

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