[Fixed]-Django queryset filtering by ISO week number

by

9👍

✅

You’re not going to be able to do this. Remember it’s not just an issue of what Python supports, Django has to communicate the filter to the database, and the database doesn’t support such complex date calculations. You can use __range, though, with a start date and end date.

👤Chris Pratt

6👍

Even simpler than using Extract function that Amit mentioned in his answer is using __week field lookup added in Django 1.11, so you can simply do:

.filter(model__date__week=datetime.date.today().isocalendar()[1])
👤radoh

2👍

ExtractWeek has been introduced in Django 1.11 for filtering based on isoweek number.

For Django 1.10 and lower versions, following solution works for filtering by iso number week on postgres database:

from django.db.models.functions import Extract
from django.db import models
@models.DateTimeField.register_lookup
class ExtractWeek(Extract):
    lookup_name = 'week'

Now do query as follows

queryset.annotate(week=ExtractWeek('date'))\
            .filter(week=week_number)
👤Amit Jaiswal

1👍

(This answer should only work for postgres, but might work for other databases.)

A quick and elegant solution for this problem would be to define these two custom transformers:

from django.db import models
from django.db.models.lookups import DateTransform

@models.DateTimeField.register_lookup
class WeekTransform(DateTransform):
    lookup_name = 'week'


@models.DateTimeField.register_lookup
class ISOYearTransform(DateTransform):
    lookup_name = 'isoyear'

Now you can query by week like this:

from django.utils.timezone import now
year, week, _ = now().isocalendar()

MyModel.objects.filter(created__isoyear=year, created__week=week)

Behinds the scenes, the Django DateTransform object uses the postgres EXTRACT function, which supports week and isoyear.

👤Yotam Ofek

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