2 files changed, 15 insertions, 6 deletions
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index 9508cb532..a00d4078a 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -276,6 +276,7 @@ class Query(object):
         return self._select_from_entity or \
             self._entity_zero().entity_zero
 
+
     @property
     def _mapper_entities(self):
         # TODO: this is wrong, its hardcoded to "primary entity" when
@@ -3086,8 +3087,9 @@ class _MapperEntity(_QueryEntity):
 class _ColumnEntity(_QueryEntity):
     """Column/expression based entity."""
 
-    def __init__(self, query, column):
+    def __init__(self, query, column, namespace=None):
         self.expr = column
+        self.namespace = namespace
 
         if isinstance(column, basestring):
             column = sql.literal_column(column)
@@ -3106,7 +3108,7 @@ class _ColumnEntity(_QueryEntity):
             for c in column._select_iterable:
                 if c is column:
                     break
-                _ColumnEntity(query, c)
+                _ColumnEntity(query, c, namespace=column)
 
             if c is not column:
                 return
@@ -3147,12 +3149,14 @@ class _ColumnEntity(_QueryEntity):
 
         if self.entities:
             self.entity_zero = list(self.entities)[0]
+        elif self.namespace is not None:
+            self.entity_zero = self.namespace
         else:
             self.entity_zero = None
 
     @property
     def entity_zero_or_selectable(self):
-        if self.entity_zero:
+        if self.entity_zero is not None:
             return self.entity_zero
         elif self.actual_froms:
             return list(self.actual_froms)[0]
diff --git a/lib/sqlalchemy/orm/util.py b/lib/sqlalchemy/orm/util.py
index 0cd5b0594..6ac03d95a 100644
--- a/lib/sqlalchemy/orm/util.py
+++ b/lib/sqlalchemy/orm/util.py
@@ -557,15 +557,20 @@ def _entity_descriptor(entity, key):
     attribute.
 
     """
-    if not isinstance(entity, (AliasedClass, type)):
-        entity = entity.class_
+    if isinstance(entity, expression.FromClause):
+        description = entity
+        entity = entity.c
+    elif not isinstance(entity, (AliasedClass, type)):
+        description = entity = entity.class_
+    else:
+        description = entity
 
     try:
         return getattr(entity, key)
     except AttributeError:
         raise sa_exc.InvalidRequestError(
                     "Entity '%s' has no property '%s'" % 
-                    (entity, key)
+                    (description, key)
                 )
 
 def _orm_columns(entity):