Django JSONField isnull 查找

Question

As far as I know you can't use __isnull lookups on django native JSONField . On the Internet I found this inactive issue. As possible workaround we can of course use these hacks:

1. model.objects.filter(field__contains={'key': None}) , which isn't so flexible since you might need to query multiple keys or whatever.

2. model.objects.exclude(field__key=True).exclude(field__key=False) , which is hacky and works only for boolean data.

I hope there is a better way ((c) Raymond Hettinger) of doing this. Any advises will be appreciated. For now, I will go with the first approach

Answer 1

According to this (see the last, closing comment) the following should work model.objects.filter(field__key=None) (But obviously you should use the Django version with the fix ).

The django docs

warn that

Since any string could be a key in a JSON object, any lookup other than those listed below will be interpreted as a key lookup. No errors are raised. Be extra careful for typing mistakes, and always check your queries work as you intend.

and here they are