#28787: QuerySet.update() fails on MySQL if a subquery references the base table
-------------------------------------+-------------------------------------
Reporter: Paulo | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.11
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Tim Graham):
* component: Uncategorized => Database layer (models, ORM)
* stage: Unreviewed => Accepted
* type: Uncategorized => Bug
Old description:
> Given the models below:
>
> {{{
> class House(models.Model):
> name = models.CharField(max_length=200)
>
> class Room(models.Model):
> name = models.CharField(max_length=200)
> house = models.ForeignKey(House, on_delete=models.CASCADE)
> }}}
>
> The following query fails:
>
> {{{
> houses_with_suites = House.objects.filter(room__name__icontains='suite')
> Room.objects.filter(house__in=houses_with_suites).update(name='suite')
> }}}
>
> With this error:
>
> {{{
> OperationalError: (1093, "You can't specify target table
> 'mysql_test_room' for update in FROM clause")
> }}}
>
> I think this has been around for a while
> (https://code.djangoproject.com/ticket/20300).
>
> I've confirmed this only happens in MySQL. It works on PostgresSQL and
> SQLite.
New description:
Given the models below:
{{{
class House(models.Model):
name = models.CharField(max_length=200)
class Room(models.Model):
name = models.CharField(max_length=200)
house = models.ForeignKey(House, on_delete=models.CASCADE)
}}}
The following query fails:
{{{
houses_with_suites = House.objects.filter(room__name__icontains='suite')
Room.objects.filter(house__in=houses_with_suites).update(name='suite')
}}}
With this error:
{{{
OperationalError: (1093, "You can't specify target table 'mysql_test_room'
for update in FROM clause")
}}}
I think this has been around for a while (#20300).
I've confirmed this only happens in MySQL. It works on PostgresSQL and
SQLite.
--
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Ticket URL: <https://code.djangoproject.com/ticket/28787#comment:2>
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