- columns from Alias objects, when used to target result-row columns, must match exactly

  to the label used in the generated statement.  This is so searching for columns in a
  result row which match aliases won't accidentally match non-aliased columns.
  fixes errors which can arise in eager loading scenarios.

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index f7514fec9..dac5d7a74 100644
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -2423,6 +2423,14 @@ class Alias(FromClause):
     def _get_from_objects(self, **modifiers):
         return [self]
 
+    def _proxy_column(self, column):
+        c = column._make_proxy(self)
+        # send a note to ResultProxy to not "approximate"
+        # this column based on its name when targeting result columns
+        # see test/sql/query.py QueryTest.test_exact_match
+        c._exact_match = True
+        return c
+
     bind = property(lambda s: s.selectable.bind)
 
 class _ColumnElementAdapter(ColumnElement):