[1.8.x] Fixed #24605 -- Fixed incorrect reference to alias in subquery.

Thanks to charettes and priidukull for investigating the issue, and to
kurevin for the report.

Backport of 355c5edd9390caad5725375abca03460805f663b from master

1 files changed, 2 insertions, 1 deletions

diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index a695025167..810031f47e 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -338,7 +338,8 @@ class SQLCompiler(object):
         if name in self.quote_cache:
             return self.quote_cache[name]
         if ((name in self.query.alias_map and name not in self.query.table_map) or
-                name in self.query.extra_select or name in self.query.external_aliases):
+                name in self.query.extra_select or (
+                    name in self.query.external_aliases and name not in self.query.table_map)):
             self.quote_cache[name] = name
             return name
         r = self.connection.ops.quote_name(name)