diff options
Diffstat (limited to 'lib/sqlalchemy/sql/selectable.py')
| -rw-r--r-- | lib/sqlalchemy/sql/selectable.py | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py index 2a221cdf0..3a90f77fb 100644 --- a/lib/sqlalchemy/sql/selectable.py +++ b/lib/sqlalchemy/sql/selectable.py @@ -4428,15 +4428,24 @@ class _SelectFromElements(object): # note this does not include elements # in _setup_joins or _legacy_setup_joins - return itertools.chain( - itertools.chain.from_iterable( - [element._from_objects for element in self._raw_columns] - ), - itertools.chain.from_iterable( - [element._from_objects for element in self._where_criteria] - ), - self._from_obj, - ) + seen = set() + for element in self._raw_columns: + for fr in element._from_objects: + if fr in seen: + continue + seen.add(fr) + yield fr + for element in self._where_criteria: + for fr in element._from_objects: + if fr in seen: + continue + seen.add(fr) + yield fr + for element in self._from_obj: + if element in seen: + continue + seen.add(element) + yield element class Select( |