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djangodjango-modelsdjango-orm

Django: Group by date over a datetime field

I have for example a model like this:

class Transaction(models.Model):
    amount = models.FloatField()
    seller = models.ForeignKey(User, related_name='sells', on_delete=models.CASCADE)
    buyer = models.ForeignKey(User, related_name='purchased', on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now_add=True)

I want to group by all transactions seperated by each date and find some of them. If the created_at is of type DateField I could simply find the count on each day by this query:

Transaction.objects..values('created_at').annotate(count=Count('created_at_date')

But this doesn't work DateTimeFeilds.

My question is how can i find total count of transactions for each date for this model type.

Solution

  • The following will work for django 2.1 and above. 

     Transaction.objects.values('created_at__date').annotate(count=Count('id')).values('created_at__date', 'count').order_by('created_at__date')

    You need to use __date after the name for lookup and need to put an order_by at the end.

    Not sure about the previous django versions.