CODEWITHSUNDEEP
pythondjangodjango-1.9django-jsonfield
ryche
ryche

Reputation: 2094

Django 1.9 JSONField order_by

I have the following django model that contains JSONField:

class RatebookDataEntry(models.Model):
    data = JSONField(blank=True, default=[])
    last_update = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name_plural = 'Ratebook data entries'

And data field contains this json:

{
    "annual_mileage": 15000, 
    "description": "LEON DIESEL SPORT COUPE", 
    "body_style": "Coupe", 
    "range_name": "LEON", 
    "co2_gkm_max": 122, 
    "manufacturer_name": "SEAT"
}

Can I sort queryset by one of the data fields? This query doesn't work.

RatebookDataEntry.objects.all().order_by("data__manufacturer_name")

Upvotes: 18

Views: 12528

Answers (7)

Daniil Ryzhkov
Daniil Ryzhkov

Reputation: 7596

As Julien mentioned ordering on JSONField is not yet supported in Django. But it's possible via RawSQL using PostgreSQL functions for jsonb. In OP's case:

from django.db.models.expressions import RawSQL
RatebookDataEntry.objects.all().order_by(RawSQL("data->>%s", ("manufacturer_name",)))

Upvotes: 27

James Mishra
James Mishra

Reputation: 4510

This question (and most of the answers) are for Django 1.9. However, Django versions 3.1 and newer support JSONField on recent versions of MariaDB, MySQL, Oracle, PostgreSQL, and SQLite.

The behavior around creating/maintaining indexes on JSON fields may vary across database engines, but ordering should work with the exact syntax you have in your question:

RatebookDataEntry.objects.all().order_by("data__manufacturer_name")

Note that unless you do further filtering, this will include database rows where the manufacturer_name key in the data JSONField does not exist.

Upvotes: 18

Mujeeb
Mujeeb

Reputation: 1225

I had to do the following to order by date (using to_date). Assuming there's another value in data called created_date (e.g. 03.06.2019).

RatebookDataEntry.objects.all().order_by(
        OrderBy(
            RawSQL("to_date(values->>%s, 'DD.MM.YYYY')", ("created_date",)),
            descending=True,
        )
    )

Upvotes: 0

theY4Kman
theY4Kman

Reputation: 6105

Since Django 1.11, django.contrib.postgres.fields.jsonb.KeyTextTransform can be used instead of RawSQL

from django.contrib.postgres.fields.jsonb import KeyTextTransform

qs = RatebookEntry.objects.all()
qs = qs.annotate(manufacturer_name=KeyTextTransform('manufacturer_name', 'data'))
qs = qs.order_by('manufacturer_name')
# or...
qs = qs.order_by('-manufacturer_name')

On Django 1.10, you'll have to subclass KeyTransform yourself:

from django.contrib.postgres.fields.jsonb import KeyTransform

class KeyTextTransform(KeyTransform):
    operator = '->>'
    nested_operator = '#>>'
    _output_field = TextField()

Note: the difference between KeyTransform and KeyTextTransform is that KeyTransform will return the JSON representation of the object, whereas KeyTextTransform will return the value of the object.

For example, if data is {"test": "stuff"}, KeyTextTransform will return 'stuff', whereas KeyTransform will return '"stuff"' (which can be parsed by json.loads)

Upvotes: 17

yekta
yekta

Reputation: 3433

This is an upcoming feature which has already been added and will be released in Django 2.1, expected release of August 2018.

See https://code.djangoproject.com/ticket/24747 and https://github.com/django/django/pull/8528 for details.

Upvotes: 6

Daniele Guido
Daniele Guido

Reputation: 111

Following Daniil Ryzhkov answer and Eugene Prikazchikov comment, you should be able to sort ASC and DESC on JSON data fields without annotating your queryset, by using both RawSQL and OrderBy. Also, you can perform case insensitive sorting by adding LOWER:

from django.db.models.expressions import RawSQL, OrderBy

RatebookDataEntry.objects.all().order_by(OrderBy(RawSQL("LOWER(data->>%s)", ("manufacturer_name",)), descending=True))

To compare integers fields, you can cast as integer:

RatebookDataEntry.objects.all().order_by(OrderBy(RawSQL("cast(data->>%s as integer)", ("annual_mileage",)), descending=True))

Upvotes: 10

Julien Salinas
Julien Salinas

Reputation: 1139

The documentation does not mention this possibility. It seems you cannot use order_by based on a JSONfield for the moment.

Upvotes: 3

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