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Fixed #20600 -- ordered distinct(*fields) in subqueries

This commit is contained in:
Anssi Kääriäinen 2013-10-11 00:12:10 +03:00
parent ccbba98131
commit b1b04df065
3 changed files with 53 additions and 17 deletions
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18
django/db/models/sql/compiler.py
View File

@ -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

28
tests/distinct_on_fields/tests.py
View File

@ -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
)

16
tests/extra_regress/tests.py
View File

@ -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)