I need to query a model by a JsonField
, I want to get all records that have empty value ([]):
I used MyModel.objects.filter(myjsonfield=[])
but it's not working, it returns 0 result though there's records having myjsonfield=[]
Use the dunder __exact
for this. The __isnull=True
does not work because the JSONField is technically not null.
MyModel entries where myjsonfield
is empty:
MyModel.objects.include(myjsonfield__exact=[])
MyModel entries where myjsonfield
is not empty:
MyModel.objects.exclude(myjsonfield__exact=[])
https://docs.djangoproject.com/en/3.1/ref/models/querysets/#std:fieldlookup-exact
I believe if you've set the default=dict
in your model then you should use {}
(eg: myjsonfield__exact={}
) instead of []
but I haven't tested this.
JSONfield 应该是default={}
即字典,而不是列表。
Firstly, Django actually recommends that you declare JSONField with immutable/callable default values. For your example:
class MyModel(models.Model): myjsonfield = models.JSONField(null=True, default=list)
Secondly, to query by null
JSONField:
MyModel.objects.filter(myjsonfield__isnull=True)
To query for fields having default
value ( []
in your case):
MyModel.objects.filter(myjsonfield__exact=[])
See https://docs.djangoproject.com/en/4.0/topics/db/queries/#querying-jsonfield for more details and examples.
试试MyModel.objects.filter(myjsonfield='[]')
。
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