django order by isnull value?

Question

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?

score 12 · Accepted Answer · answered Mar 10 '12 at 18:20

12

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')

answered Mar 10 '12 at 18:20

second

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Jakub QB Dorňák · Answer 2 · 2020-07-07T09:56:11.007

7

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')

edited Jul 07 '20 at 09:56

answered Jul 07 '20 at 09:13

Jakub QB Dorňák

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Interesting ne take on the problem! – Andy Jul 07 '20 at 10:37

score -3 · Answer 3 · answered Mar 10 '12 at 18:23

-3

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')

answered Mar 10 '12 at 18:23

Zain Khan

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This imposes a sorting by date for non-null values, instead the asker is just wanting 2 groups, null and non-null. – Rebs Oct 02 '14 at 07:04

django order by isnull value?

3 Answers3