figured out how a Select can be in its own _froms list, changed assertion to just a continue

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index 61b3d277a..ce33810a5 100644
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -1455,6 +1455,7 @@ class Select(_SelectBaseMixin, FromClause):
         self._correlator = Select._CorrelatedVisitor(self, False)
         self._wherecorrelator = Select._CorrelatedVisitor(self, True)
 
+
         self.group_by(*(group_by or [None]))
         self.order_by(*(order_by or [None]))
         
@@ -1543,8 +1544,9 @@ class Select(_SelectBaseMixin, FromClause):
     def _locate_oid_column(self):
         for f in self._froms.values():
             if f is self:
-                # TODO: why would we be in our own _froms list ?
-                raise exceptions.AssertionError("Select statement should not be in its own _froms list")
+                # we might be in our own _froms list if a column with us as the parent is attached,
+                # which includes textual columns. 
+                continue
             oid = f.oid_column
             if oid is not None:
                 return oid