Refs #27849 -- Fixed filtered aggregates crash on filters that match everything.

2 files changed, 25 insertions, 11 deletions

diff --git a/django/db/models/aggregates.py b/django/db/models/aggregates.py
index ec21e5fd11..ab38a33bf0 100644
--- a/django/db/models/aggregates.py
+++ b/django/db/models/aggregates.py
@@ -105,17 +105,18 @@ class Aggregate(Func):
         if self.filter:
             if connection.features.supports_aggregate_filter_clause:
                 filter_sql, filter_params = self.filter.as_sql(compiler, connection)
-                template = self.filter_template % extra_context.get(
-                    "template", self.template
-                )
-                sql, params = super().as_sql(
-                    compiler,
-                    connection,
-                    template=template,
-                    filter=filter_sql,
-                    **extra_context,
-                )
-                return sql, (*params, *filter_params)
+                if filter_sql:
+                    template = self.filter_template % extra_context.get(
+                        "template", self.template
+                    )
+                    sql, params = super().as_sql(
+                        compiler,
+                        connection,
+                        template=template,
+                        filter=filter_sql,
+                        **extra_context,
+                    )
+                    return sql, (*params, *filter_params)
             else:
                 copy = self.copy()
                 copy.filter = None
diff --git a/tests/aggregation/test_filter_argument.py b/tests/aggregation/test_filter_argument.py
index caf2cd3d6f..3ef0401d4d 100644
--- a/tests/aggregation/test_filter_argument.py
+++ b/tests/aggregation/test_filter_argument.py
@@ -205,3 +205,16 @@ class FilteredAggregateTests(TestCase):
             max_rating=Max("rating", filter=Q(rating__in=[]))
         )
         self.assertEqual(aggregate, {"max_rating": None})
+
+    def test_filtered_aggregate_full_condition(self):
+        book = Book.objects.annotate(
+            authors_count=Count(
+                "authors",
+                filter=~Q(authors__in=[]),
+            ),
+        ).get(pk=self.b1.pk)
+        self.assertEqual(book.authors_count, 2)
+        aggregate = Book.objects.aggregate(
+            max_rating=Max("rating", filter=~Q(rating__in=[]))
+        )
+        self.assertEqual(aggregate, {"max_rating": 4.5})