#26602: RawSQL window functions break count()
-------------------------------------+-------------------------------------
Reporter: daggaz | Owner: nobody
Type: Uncategorized | Status: new
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: QuerySet.extra | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by jarshwah):
* cc: josh.smeaton@… (added)
* version: 1.9 => master
* stage: Unreviewed => Accepted
Comment:
This happens because RawSQL defines:
{{{
def get_group_by_cols(self):
return [self]
}}}
It'd be helpful if there was a way to disable grouping in an easy way. For
the moment, you should be able to do something like:
{{{
window = RawSQL("SUM(amount) OVER (ORDER BY created)", [])
window.get_group_by_cols = lambda: []
qs = A.objects.annotate(total=window)
qs.count()
# Or..
RawAggregate(RawSQL):
contains_aggregate = True # may not be necessary in newer django
versions
def get_group_by_cols(self):
return []
qs = A.objects.annotate(total=RawAggregate("SUM(amount) OVER (ORDER BY
created)", []))
}}}
Can you let me know if this workaround helps you?
In the meantime, I think it's worth figuring out how we want to treat
RawSQL when it should not be doing group bys, so I'm accepting on that
basis.
Two options I see. First, we can define a whole new class as I've done
above - like RawAggregate. Second, we could use a kwarg to RawSQL to tweak
whether or not it contains aggregate code.
{{{
RawSQL('SELECT SUM() ..', [], grouping=False)
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/26602#comment:2>
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