#28560: distinct() on ordered queryset with restricted list of columns returns
incorrect result
-------------------------------------+-------------------------------------
Reporter: felixxm | Owner: felixxm
Type: Bug | Status: assigned
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: distinct values | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by felixxm:
Old description:
> `distinct()` doesn't work properly on `None` values. If we select columns
> with `null` values then `distinct()` returns each of them instead of
> single `None`, e.g. (based on `queries/tests.py`):
>
> {{{
> >>>
> list(Item.objects.filter(modified__isnull=True).values_list('modified',
> flat=True).distinct())
> [None, None, None]
> }}}
>
> instead of `[None]`.
New description:
I think we should raise `NotSupportedError` when `distinct()` is used with
`values()` (or `values_list()`) on ordered queryset and a list of fields
in `values()` doesn't contain all fields from `ORDER BY`. It cannot return
correct result because columns from `ORDER BY` clause must be included in
`SELECT`.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/28560#comment:3>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/065.43b99a2c2038f9008c6449b571aa6fc7%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
