Commit adc57632 authored by Anssi Kääriäinen's avatar Anssi Kääriäinen Committed by Tim Graham
Browse files

Fixed #24748 -- Fixed incorrect GROUP BY on MySQL in some queries 

When the query's model had a self-referential foreign key, the
compiler.get_group_by() code incorrectly used the self-referential
foreign key's column (for example parent_id) as GROUP BY clause
when it should have used the model's primary key column (id).
parent be9d6453

django/db/models/sql/compiler.py

+5 −2
Original line number Diff line number Diff line
@@ -143,9 +143,12 @@ class SQLCompiler(object): 
            # then also add having expressions to group by.

            pk = None

            for expr in expressions:

                if (expr.output_field.primary_key and

                        getattr(expr.output_field, 'model') == self.query.model):

                # Is this a reference to query's base table primary key? If the

                # expression isn't a Col-like, then skip the expression.

                if (getattr(expr, 'target', None) == self.query.model._meta.pk and

                        getattr(expr, 'alias', None) == self.query.tables[0]):

                    pk = expr

                    break

            if pk:

                # MySQLism: Columns in HAVING clause must be added to the GROUP BY.

                expressions = [pk] + [expr for expr in expressions if expr in having]

docs/releases/1.8.2.txt

+3 −0
Original line number Diff line number Diff line
@@ -17,3 +17,6 @@ Bugfixes 
* Corrected join promotion for ``Case`` expressions. For example, annotating a

  query with a  ``Case`` expression could unexpectedly filter out results

  (:ticket:`24766`).



* Fixed incorrect GROUP BY clause generation on MySQL when the query's model

  has a self-referential foreign key (:ticket:`24748`).

tests/aggregation_regress/models.py

+5 −0
Original line number Diff line number Diff line
@@ -104,3 +104,8 @@ class Bravo(models.Model): 
class Charlie(models.Model):

    alfa = models.ForeignKey(Alfa, null=True)

    bravo = models.ForeignKey(Bravo, null=True)





class SelfRefFK(models.Model):

    name = models.CharField(max_length=50)

    parent = models.ForeignKey('self', null=True, blank=True, related_name='children')

tests/aggregation_regress/tests.py

+13 −1
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ from django.utils import six 


from .models import (

    Alfa, Author, Book, Bravo, Charlie, Clues, Entries, HardbackBook, ItemTag,

    Publisher, Store, WithManualPK,

    Publisher, SelfRefFK, Store, WithManualPK,

)
@@ -1277,3 +1277,15 @@ class JoinPromotionTests(TestCase): 
    def test_non_nullable_fk_not_promoted(self):

        qs = Book.objects.annotate(Count('contact__name'))

        self.assertIn(' INNER JOIN ', str(qs.query))





class SelfReferentialFKTests(TestCase):

    def test_ticket_24748(self):

        t1 = SelfRefFK.objects.create(name='t1')

        SelfRefFK.objects.create(name='t2', parent=t1)

        SelfRefFK.objects.create(name='t3', parent=t1)

        self.assertQuerysetEqual(

            SelfRefFK.objects.annotate(num_children=Count('children')).order_by('name'),

            [('t1', 2), ('t2', 0), ('t3', 0)],

            lambda x: (x.name, x.num_children)

        )