I don't think there can be a performant way to compare two querysets. Moreover, which features should be considered in equality would be very complicated, when you consider the more involved parts of the API like database functions, annotations, subqueries, etc.
One can check via the database if two queries give the same results with the difference() method: https://docs.djangoproject.com/en/4.0/ref/models/querysets/#django.db.models.query.QuerySet.difference . For example: querysets_the_same = not qs1.difference(qs2).exists() On Wed, May 11, 2022 at 2:41 PM mohamad ali mehdizadeh <am.civi...@gmail.com> wrote: > Python `==` operator does not check references, it checks values, so qs2 > is a copy of qs1 but its value is the same so == must be True as it's not > now. > So I have a simple solution. > def __eq__(self, other): > if not isinstance(other, self.__class__): > raise ValueError('Cannot compare a QuerySet to a non-QuerySet.') > if not self.query.can_filter(): > return NotImplemented > return not self.difference(other).union(other.difference(self)).exists() > > On Wednesday, May 11, 2022 at 12:14:51 AM UTC+4:30 ma...@wpsoft.at wrote: > >> I am not Agree. >> >> qs1.all() it is copy from qs1, the new object. >> >> >> >> I already try to write QuerySet compare on the Django 1.4 and i remember, >> >> that str(qs1.query) can be different as str(qs2.query), I am not Shure. >> >> >> >> Mit freundlichen Grüßen, >> >> DI Mag. Maxim Danilov >> >> >> >> +43(681)207 447 76 >> >> ma...@wpsoft.at >> >> >> >> *From:* django-d...@googlegroups.com [mailto:django-d...@googlegroups.com] >> *On Behalf Of *mohamad ali mehdizadeh >> *Sent:* Tuesday, May 10, 2022 5:09 PM >> *To:* Django developers (Contributions to Django itself) < >> django-d...@googlegroups.com> >> *Subject:* Equality check for two QuerySet >> >> >> >> Hi. >> Why we don't have __eq__ for QuerySets, here is an example: >> ``` >> >> qs1 = Model.objects.all() >> >> qs2 = qs1.all() >> >> qs1 == qs2 >> >> ``` >> >> output: False >> >> as we know these two are the same by value! >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Django developers (Contributions to Django itself)" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to django-develop...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/django-developers/80e878f8-8701-40ad-92a0-5c689df27ec2n%40googlegroups.com >> <https://groups.google.com/d/msgid/django-developers/80e878f8-8701-40ad-92a0-5c689df27ec2n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- > You received this message because you are subscribed to the Google Groups > "Django developers (Contributions to Django itself)" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to django-developers+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-developers/a930c0e1-6cc9-4894-8922-a07aedad3fcdn%40googlegroups.com > <https://groups.google.com/d/msgid/django-developers/a930c0e1-6cc9-4894-8922-a07aedad3fcdn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CAMyDDM2tir72pSEDoRUFLB%2Bof1tCcokEUZ%2BRED6U8GJQduqXVg%40mail.gmail.com.
