Fixed #27862 -- Fixed incorrectly quoted table aliases in Subquery SQL.

Add aliases from resolved querysets to the parent query's external
aliases to prevent those aliases from being quoted.

Thanks to Vasily Stepanov for the report and Tim Graham for the review.

2 files changed, 15 insertions, 1 deletions

diff --git a/django/db/models/expressions.py b/django/db/models/expressions.py
index 8361e42d20..ed57599a15 100644
--- a/django/db/models/expressions.py
+++ b/django/db/models/expressions.py
@@ -940,10 +940,15 @@ class Subquery(Expression):
 
         def resolve(child):
             if hasattr(child, 'resolve_expression'):
-                return child.resolve_expression(
+                resolved = child.resolve_expression(
                     query=query, allow_joins=allow_joins, reuse=reuse,
                     summarize=summarize, for_save=for_save,
                 )
+                # Add table alias to the parent query's aliases to prevent
+                # quoting.
+                if hasattr(resolved, 'alias'):
+                    clone.queryset.query.external_aliases.add(resolved.alias)
+                return resolved
             return child
 
         resolve_all(clone.queryset.query.where)
diff --git a/tests/expressions/tests.py b/tests/expressions/tests.py
index 38258e0dd0..5483a17fd1 100644
--- a/tests/expressions/tests.py
+++ b/tests/expressions/tests.py
@@ -516,6 +516,15 @@ class BasicExpressionsTests(TestCase):
             [{'salary': 10, 'total_employees': 2300}, {'salary': 20, 'total_employees': 35}],
         )
 
+    def test_subquery_references_joined_table_twice(self):
+        inner = Company.objects.filter(
+            num_chairs__gte=OuterRef('ceo__salary'),
+            num_employees__gte=OuterRef('point_of_contact__salary'),
+        )
+        # Another contrived example (there is no need to have a subquery here)
+        outer = Company.objects.filter(pk__in=Subquery(inner.values('pk')))
+        self.assertFalse(outer.exists())
+
 
 class IterableLookupInnerExpressionsTests(TestCase):
     @classmethod