[Django]-How to write a query to get find value in a json field in django

If you are using the django-jsonfield package, then this is simple. Say you have a model like this:

from jsonfield import JSONField
class User(models.Model):
    jsonfield = JSONField()

Then to search for records with a specific username, you can just do this:

User.objects.get(jsonfield__contains={'username':username})

Since Django 1.9, you have been able to use PostgreSQL’s native JSONField. This makes search JSON very simple. In your example, this query would work:

User.objects.get(jsonfield__username='chingo')

If you have an older version of Django, or you are using the Django JSONField library for compatibility with MySQL or something similar, you can still perform your query.

In the latter situation, jsonfield will be stored as a text field and mapped to a dict when brought into Django. In the database, your data will be stored like this

{"username":"chingo","reputation":"5"}

Therefore, you can simply search the text. Your query in this siutation would be:

User.objects.get(jsonfield__contains='"username":"chingo"')

2019: As @freethebees points out it’s now as simple as:

User.objects.get(jsonfield__username='chingo')

But as the doc examples mention you can query deeply, and if the json is an array you can use an integer to index it:

https://docs.djangoproject.com/en/2.2/ref/contrib/postgres/fields/#querying-jsonfield

>>> Dog.objects.create(name='Rufus', data={
...     'breed': 'labrador',
...     'owner': {
...         'name': 'Bob',
...         'other_pets': [{
...             'name': 'Fishy',
...         }],
...     },
... })
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': None})

>>> Dog.objects.filter(data__breed='collie')
<QuerySet [<Dog: Meg>]>

>>> Dog.objects.filter(data__owner__name='Bob')
<QuerySet [<Dog: Rufus>]>

>>> Dog.objects.filter(data__owner__other_pets__0__name='Fishy')
<QuerySet [<Dog: Rufus>]>

Although this is for postgres, I believe it works the same in other DBs like MySQL

• Postgres: https://docs.djangoproject.com/en/2.2/ref/contrib/postgres/fields/#querying-jsonfield
• MySQL: https://django-mysql.readthedocs.io/en/latest/model_fields/json_field.html#querying-jsonfield

If you use PostgreSQL you can use raw sql to solve problem.

username = 'chingo'
SQL_QUERY = "SELECT true FROM you_table WHERE jsonfield::json->>'username' = '%s'"
User.objects.extra(where=[SQL_EXCLUDE % username]).get()

where you_table is name of table in your database.

Any methods when you work with JSON like with plain text – looking like very bad way.
So, also I think that you need a better schema of database.

Here is the way I have found out that will solve your problem:

search_filter = '"username":{0}'.format(username)
query = User.objects.get(jsonfield__contains=search_filter)

Hope this helps.

You can’t do that. Use normal database fields for structured data, not JSON blobs.

If you need to search on JSON data, consider using a noSQL database like MongoDB.