Fixed #20600 -- ordered distinct(*fields) in subqueries (b1b04df0) · Commits · Dom Sekotill / django

django/db/models/sql/compiler.py

+16 −10

Original line number	Diff line number	Diff line
		@@ -164,7 +164,7 @@ class SQLCompiler(object):
		Used when nesting this query inside another.
		"""
		obj = self.query.clone()
		if obj.low_mark == 0 and obj.high_mark is None:
		if obj.low_mark == 0 and obj.high_mark is None and not self.query.distinct_fields:
		# If there is no slicing in use, then we can safely drop all ordering
		obj.clear_ordering(True)
		return obj.get_compiler(connection=self.connection).as_sql()
		@@ -364,6 +364,10 @@ class SQLCompiler(object):

		params = []
		ordering_params = []
		# For plain DISTINCT queries any ORDER BY clause must appear
		# in SELECT clause.
		# http://www.postgresql.org/message-id/27009.1171559417@sss.pgh.pa.us
		must_append_to_select = distinct and not self.query.distinct_fields
		for pos, field in enumerate(ordering):
		if field == '?':
		result.append(self.connection.ops.random_function_sql())
		@@ -388,7 +392,7 @@ class SQLCompiler(object):
		if (table, col) not in processed_pairs:
		elt = '%s.%s' % (qn(table), col)
		processed_pairs.add((table, col))
		if not distinct or elt in select_aliases:
		if not must_append_to_select or elt in select_aliases:
		result.append('%s %s' % (elt, order))
		group_by.append((elt, []))
		elif not self.query._extra or get_order_dir(field)[0] not in self.query._extra:
		@@ -400,20 +404,22 @@ class SQLCompiler(object):
		if (table, col) not in processed_pairs:
		elt = '%s.%s' % (qn(table), qn2(col))
		processed_pairs.add((table, col))
		if distinct and elt not in select_aliases:
		if must_append_to_select and elt not in select_aliases:
		ordering_aliases.append(elt)
		result.append('%s %s' % (elt, order))
		group_by.append((elt, []))
		else:
		elt = qn2(col)
		if col not in self.query.extra_select:
		if must_append_to_select:
		sql = "(%s) AS %s" % (self.query.extra[col][0], elt)
		ordering_aliases.append(sql)
		ordering_params.extend(self.query.extra[col][1])
		result.append('%s %s' % (elt, order))
		else:
		result.append("(%s) %s" % (self.query.extra[col][0], order))
		params.extend(self.query.extra[col][1])
		else:
		if distinct and col not in select_aliases:
		ordering_aliases.append(elt)
		ordering_params.extend(params)
		result.append('%s %s' % (elt, order))
		group_by.append(self.query.extra[col])
		self.ordering_aliases = ordering_aliases

tests/distinct_on_fields/tests.py

+21 −7

Original line number	Diff line number	Diff line
		@@ -16,13 +16,13 @@ class DistinctOnTests(TestCase):
		Tag.objects.create(name='t4', parent=t3)
		Tag.objects.create(name='t5', parent=t3)

		p1_o1 = Staff.objects.create(id=1, name="p1", organisation="o1")
		p2_o1 = Staff.objects.create(id=2, name="p2", organisation="o1")
		p3_o1 = Staff.objects.create(id=3, name="p3", organisation="o1")
		Staff.objects.create(id=4, name="p1", organisation="o2")
		p1_o1.coworkers.add(p2_o1, p3_o1)
		StaffTag.objects.create(staff=p1_o1, tag=t1)
		StaffTag.objects.create(staff=p1_o1, tag=t1)
		self.p1_o1 = Staff.objects.create(id=1, name="p1", organisation="o1")
		self.p2_o1 = Staff.objects.create(id=2, name="p2", organisation="o1")
		self.p3_o1 = Staff.objects.create(id=3, name="p3", organisation="o1")
		self.p1_o2 = Staff.objects.create(id=4, name="p1", organisation="o2")
		self.p1_o1.coworkers.add(self.p2_o1, self.p3_o1)
		StaffTag.objects.create(staff=self.p1_o1, tag=t1)
		StaffTag.objects.create(staff=self.p1_o1, tag=t1)

		celeb1 = Celebrity.objects.create(name="c1")
		celeb2 = Celebrity.objects.create(name="c2")
		@@ -114,3 +114,17 @@ class DistinctOnTests(TestCase):
		# distinct + aggregate not allowed
		with self.assertRaises(NotImplementedError):
		Celebrity.objects.distinct('id').aggregate(Max('id'))

		def test_distinct_on_in_ordered_subquery(self):
		qs = Staff.objects.distinct('name').order_by('name', 'id')
		qs = Staff.objects.filter(pk__in=qs).order_by('name')
		self.assertQuerysetEqual(
		qs, [self.p1_o1, self.p2_o1, self.p3_o1],
		lambda x: x
		)
		qs = Staff.objects.distinct('name').order_by('name', '-id')
		qs = Staff.objects.filter(pk__in=qs).order_by('name')
		self.assertQuerysetEqual(
		qs, [self.p1_o2, self.p2_o1, self.p3_o1],
		lambda x: x
		)

tests/extra_regress/tests.py

+16 −0

Original line number	Diff line number	Diff line
		@@ -347,3 +347,19 @@ class ExtraRegressTests(TestCase):
		['<TestObject: TestObject: a,a,a>', '<TestObject: TestObject: b,a,a>'],
		ordered=False
		)

		def test_extra_values_distinct_ordering(self):
		t1 = TestObject.objects.create(first='a', second='a', third='a')
		t2 = TestObject.objects.create(first='a', second='b', third='b')
		qs = TestObject.objects.extra(
		select={'second_extra': 'second'}
		).values_list('id', flat=True).distinct()
		self.assertQuerysetEqual(
		qs.order_by('second_extra'), [t1.pk, t2.pk], lambda x: x)
		self.assertQuerysetEqual(
		qs.order_by('-second_extra'), [t2.pk, t1.pk], lambda x: x)
		# Note: the extra ordering must appear in select clause, so we get two
		# non-distinct results here (this is on purpose, see #7070).
		self.assertQuerysetEqual(
		qs.order_by('-second_extra').values_list('first', flat=True),
		['a', 'a'], lambda x: x)