CODEWITHSUNDEEP
pythondjangodjango-1.4
dabadaba
dabadaba

Reputation: 9542

Django QuerySet: filter by the value of another field

I have a model I wish to filter by its attribute a. The model also has another attribute b. I am trying to filter entries where a is 0 or a has the value of the b attribute (for each row, obviously). How can I filter by the value of another column?

Here is what I have tried, and the missing piece:

MyModel.objects.filter(Q(a=0) | Q(a=???)) # ??? is to be the value of the `b` column

I am using Django 1.4 and I know it is an old version that is no longer supported but unfortunately performing the upgrade is not up to me.

Upvotes: 11

Views: 14830

Answers (2)

Moses Koledoye
Moses Koledoye

Reputation: 78554

I think you can use an F expression with your Q object:

MyModel.objects.filter(Q(a=0) | Q(a=F('b')))

I'll also suggest you schedule your upgrade now, otherwise, you'll be missing out on other features and security fixes.

Upvotes: 20

Osiris92
Osiris92

Reputation: 191

You can use the F model for comparing two fields.

from django.db.models import F
MyModel.objects.filter(a__exact = F('b'))

So for your joint query you can use something like,

MyModel.objects.filter(Q(a=0) | Q(a__exact=F('b')))

Upvotes: 6

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