Django Rest : AssertionError: Cannot combine a unique query with a non-unique query

user_9522658 0
Viewed 1586

I am trying to get a queryset with unique instances of a model project. when I try to combine multiple querysets with & operator like

projects = (q1_projects & q2_projects & q3_projects)

I get this error

AssertionError: Cannot combine a unique query with a non-unique query.

django-rest-framework django-queryset python-3.x django operators
1 Answers

As quoted by ruddra

You can use union() to combine different querysets like this:

q1_projects = Model.objects.filter(...)
q2_projects = Model.objects.filter(...)
q3_projects = Model.objects.filter(...)

projects = q1_projects.union(q2_projects, q3_projects)

That will give same result as:

projects = q1_projects & q2_projects & q3_projects

Note: The UNION operator selects only distinct values by default. To allow duplicate values, use the all=True argument.

But if you want to order_by on the ForeignKey, you have to use select()

user_112820770
Related