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How to merge Django model query results?
I have to modify a legacy Django web application where there are 2 tables to store the same information using the same database structure, and the only difference is the names of the tables (and the corresponding Django models):
-
ProgramAAssignmentsmodel forprogram_a_assignmentstable -
ProgramBAssignmentsmodel forprogram_b_assignmentstable
They have 2 distinct views that query these models like so:
ProgramAAssignments.objects.all().order_by('-assignment_date')
ProgramBAssignments.objects.all().order_by('-assignment_date')
I decided to leave the database untouched and just combine the views, but don't know how to merge these queries.
1 answer
Just found the How Can I Combine Two or More QuerySets in a Django View? article by James W. that perfectly answers my question (and just learned that a "Django model query" is called a QuerySet). To sum up:
Do the QuerySets belong to the same model?
-
YES: use to
|union operator.model_combination = model_set1 | model_set2 | model_set3 -
NO: use
union().model_combination = model_set1.union(model_set2, all=True)
The "shape" of the data in my QuerySets were the same, but coming from different models, so using union() worked like a charm.
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