I have a model:
class Zone(models.Model):
name = models.CharField(max_length=128)
users = models.ManyToManyField(User, related_name='zones', null=True, blank=True)
And I need to contruct a filter along the lines of:
u = User.objects.filter(...zones contains a particular zone...)
It has to be a filter on User and it has to be a single filter parameter. The reason for this is that I am constructing a URL querystring to filter the admin user changelist: http://myserver/admin/auth/user/?zones=3
It seems like it should be simple but my brain isn't cooperating!
Just restating what Tomasz said.
There are many examples of FOO__in=...
style filters in the many-to-many and many-to-one tests. Here is syntax for your specific problem:
users_in_1zone = User.objects.filter(zones__id=<id1>)
# same thing but using in
users_in_1zone = User.objects.filter(zones__in=[<id1>])
# filtering on a few zones, by id
users_in_zones = User.objects.filter(zones__in=[<id1>, <id2>, <id3>])
# and by zone object (object gets converted to pk under the covers)
users_in_zones = User.objects.filter(zones__in=[zone1, zone2, zone3])
The double underscore (__) syntax is used all over the place when working with querysets.