[Django]-Django: Group by date (day, month, year)

Just a small addition to @tback answer:
It didn’t work for me with Django 1.10.6 and postgres. I added order_by() at the end to fix it.

from django.db.models.functions import TruncMonth
Sales.objects
    .annotate(month=TruncMonth('timestamp'))  # Truncate to month and add to select list
    .values('month')                          # Group By month
    .annotate(c=Count('id'))                  # Select the count of the grouping
    .order_by()

Another approach is to use ExtractMonth. I ran into trouble using TruncMonth due to only one datetime year value being returned. For example, only the months in 2009 were being returned. ExtractMonth fixed this problem perfectly and can be used like below:

from django.db.models.functions import ExtractMonth
Sales.objects
    .annotate(month=ExtractMonth('timestamp')) 
    .values('month')                          
    .annotate(count=Count('id'))                  
    .values('month', 'count')  

    metrics = {
        'sales_sum': Sum('total'),
    }
    queryset = Order.objects.values('created__month')
                               .annotate(**metrics)
                               .order_by('created__month')

The queryset is a list of Order, one line per month, combining the sum of sales: sales_sum

@Django 2.1.7

Here’s my dirty method. It is dirty.

import datetime, decimal
from django.db.models import Count, Sum
from account.models import Order
d = []

# arbitrary starting dates
year = 2011
month = 12

cyear = datetime.date.today().year
cmonth = datetime.date.today().month

while year <= cyear:
    while (year < cyear and month <= 12) or (year == cyear and month <= cmonth):
        sales = Order.objects.filter(created__year=year, created__month=month).aggregate(Count('total'), Sum('total'))
        d.append({
            'year': year,
            'month': month,
            'sales': sales['total__count'] or 0,
            'value': decimal.Decimal(sales['total__sum'] or 0),
        })
        month += 1
    month = 1
    year += 1

There may well be a better way of looping years/months but that’s not really what I care about

By month:

 Order.objects.filter().extra({'month':"Extract(month from created)"}).values_list('month').annotate(Count('id'))

By Year:

 Order.objects.filter().extra({'year':"Extract(year from created)"}).values_list('year').annotate(Count('id'))

By day:

 Order.objects.filter().extra({'day':"Extract(day from created)"}).values_list('day').annotate(Count('id'))

Don’t forget to import Count

from django.db.models import Count

For django < 1.10

Here is how you can group data by arbitrary periods of time:

from django.db.models import F, Sum
from django.db.models.functions import Extract, Cast
period_length = 60*15 # 15 minutes

# Annotate each order with a "period"
qs = Order.objects.annotate(
    timestamp=Cast(Extract('date', 'epoch'), models.IntegerField()),
    period=(F('timestamp') / period_length) * period_length,
)

# Group orders by period & calculate sum of totals for each period
qs.values('period').annotate(total=Sum(field))

i have orders table in my database . i am going to count orders per month in the last 3 months

from itertools import groupby
from dateutil.relativedelta import relativedelta

date_range = datetime.now()-relativedelta(months=3)
aggs =Orders.objects.filter(created_at=date_range)\
            .extra({'date_created':"date(created_at)"}).values('date_created')

for key , group in groupby(aggs):
     print(key,len(list(group)))

created_at is datetime field. by extra function what done is taking date from datetime values. when using datetime we may not get the count correct because objects are created at different time in a day.

The for loop will print date and number of count