If you don't want to operate on Activity instances annotations you can use
the following queryset
Status.objects.annotate(
status_month=TruncMonth('status_date'),
).order_by(
'activity', 'status_month',
).values_list(
'activity', 'status_month',
).annotate(
progress_sum=Sum(actual_progress)
)
That will return an iterable of lists of the form [activity_id,
status_month, progress_sum]
If you want to annotate your Activity instances you'll need to use window
functions[0].
Simon
[0]
https://docs.djangoproject.com/en/3.0/ref/models/expressions/#window-functions
Le mardi 25 février 2020 17:55:49 UTC-5, Agnese Camellini a écrit :
>
> You should search how to make a group by activity and a partition by month
> then take each partition and sum the record up, i don't know how to do it
> in Django orm but in sql is the most effective way to solve the issue and
> it's a lot let expensive than taking all the activities and then search in
> the status Table.
> my 2 cents
> Agnese
>
> On Tue, 25 Feb 2020 at 21:07, Mario Bisiani <mariob...@gmail.com
> <javascript:>> wrote:
>
>> I tryed to search for answer but nothing yet can help me.
>>
>> I have one class model Activity and a class model Status :
>>
>> class Status(models.Model):
>> activity = models.ForeignKey(Activity, on_delete=models.CASCADE,
>> related_name="all_status")
>> status_date = models.DateField()
>> actual_progress = models.DecimalField(max_digits=3, decimal_places=2)
>>
>> I need to get last 'status_date' for each activity for each month and sum
>> up its actual_progress.
>>
>> Can't find after many research a way out.
>>
>> *Update*
>>
>> I found a way to get latest status per activity helped here Django - get
>> latest object in each relation
>> <https://stackoverflow.com/questions/52586866/django-get-latest-object-in-each-relation>
>> :
>>
>> @classmethod
>> def get_latest_by_activity_ids(cls, activity_id):
>> found = []
>> for aid in Activity.objects.all():
>>
>> found.append(cls.objects.filter(activity_id=aid).latest("status_date"))
>> return found
>>
>> This gave me a list of dates. Now I'm blocked to sum them up per month.
>>
>>
>>
>> https://stackoverflow.com/questions/60366457/get-last-instance-object-per-each-month-and-sum-per-month-in-django
>>
>>
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