Fixed #26434 -- Removed faulty clearing of ordering field when missing from explicit grouping.

Co-authored-by: Simon Charette <charette.s@gmail.com>

2 files changed, 26 insertions, 1 deletions

diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 84950d4ec0..8f9349e7eb 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -2346,7 +2346,13 @@ class Query(BaseExpression):
         query (not even the model's default).
         """
         if not force and (
-            self.is_sliced or self.distinct_fields or self.select_for_update
+            self.is_sliced
+            or self.distinct_fields
+            or self.select_for_update
+            or (
+                isinstance(self.group_by, tuple)
+                and not {*self.order_by, *self.extra_order_by}.issubset(self.group_by)
+            )
         ):
             return
         self.order_by = ()
diff --git a/tests/aggregation_regress/tests.py b/tests/aggregation_regress/tests.py
index 3e1a6a71f9..5f17169dc6 100644
--- a/tests/aggregation_regress/tests.py
+++ b/tests/aggregation_regress/tests.py
@@ -171,6 +171,25 @@ class AggregationTests(TestCase):
         for attr, value in kwargs.items():
             self.assertEqual(getattr(obj, attr), value)
 
+    def test_count_preserve_group_by(self):
+        # new release of the same book
+        Book.objects.create(
+            isbn="113235613",
+            name=self.b4.name,
+            pages=self.b4.pages,
+            rating=4.0,
+            price=Decimal("39.69"),
+            contact=self.a5,
+            publisher=self.p3,
+            pubdate=datetime.date(2018, 11, 3),
+        )
+        qs = Book.objects.values("contact__name", "publisher__name").annotate(
+            publications=Count("id")
+        )
+        self.assertEqual(qs.count(), Book.objects.count() - 1)
+        self.assertEqual(qs.order_by("id").count(), Book.objects.count())
+        self.assertEqual(qs.extra(order_by=["id"]).count(), Book.objects.count())
+
     def test_annotation_with_value(self):
         values = (
             Book.objects.filter(