1 files changed, 7 insertions, 0 deletions
diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index 0961cd4ee..4c720dfa2 100644
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -1592,6 +1592,13 @@ class ColumnCollection(util.OrderedProperties):
         The key attribute of the column will be used as the hash key
         for this dictionary.
         """
+
+        # Allow an aliased column to replace an unaliased column of the
+        # same name.
+        if self.has_key(column.name):
+            other = self[column.name]
+            if other.name == other.key:
+                del self[other.name]
         self[column.key] = column
     
     def remove(self, column):