CODEWITHSUNDEEP
djangoisnull
Andy
Andy

Reputation: 786

django order by isnull value?

i have a datetime field which can be null and id like to do qs.order_by('field__isnull', 'name') but this results in:

Join on field 'field' not permitted. Did you misspell 'isnull' for the lookup type?

Is this possible at all?

Upvotes: 9

Views: 2574

Answers (3)

Jakub QB Dorňák
Jakub QB Dorňák

Reputation: 1261

Unfortunately, Django doesn't provide function IsNull, that could be used for ordering, annotations, etc. (It does provide a query lookup, but it may only be used for filtering.) You may however define the function yourself:

from django.db.models import BooleanField, Func

class IsNull(Func):
    _output_field = BooleanField()
    arity = 1
    template = '%(expressions)s IS NULL'

Now you may order your queryset like this:

qs.order_by(IsNull('field'), 'name')

Upvotes: 7

Zain Khan
Zain Khan

Reputation: 3793

I'm hoping that your model is something like this: 

    date_deleted = models.DateTimeField(blank=True, null=True)

If True then you can do this:

qs.order_by('-date_deleted')

Upvotes: -3

second
second

Reputation: 28637

there may be better ways, but one possibility is to annotate your queryset:

from django.db.models import Count
qs.annotate(null_count=Count('field_name')).order_by('null_count')

Upvotes: 12

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