#26430: Coalesce in Aggregations ignored when EmptyResultSet returned
-------------------------------------+-------------------------------------
Reporter: ryanprater | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.9
(models, ORM) |
Severity: Normal | Resolution:
Keywords: aggregation | Triage Stage:
coalesce in queryset | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by akaariai):
Maybe we could somehow skip throwing EmptyResultSet when doing an
.aggregate() call, but throw it when doing normal queries. One idea is to
use query.add_context('in_aggregate_query', True), and then check
compiler.query.context before throwing the EmptyResultSet.
Another possible idea is to add as_python() methods to pretty much every
part of the ORM. The as_python() method would run the expressions as
Python code, so you could run whole querysets without actually touching
the database. For the case where the query for .aggregate() generates an
EmptyResultSet we would run the queryset in Python against one row having
all None values, thus producing the wanted answer. This could be extremely
convenient for testing, too. OTOH doing this properly will require at
least a couple of months of work, so this is for sure overkill for this
issue.
--
Ticket URL: <https://code.djangoproject.com/ticket/26430#comment:4>
Django <https://code.djangoproject.com/>
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