- Fixed a regression that was incorrectly fixed in 1.0.0b4

(hence becoming two regressions); reports that
SELECT statements would GROUP BY a label name and fail was misconstrued
that certain backends such as SQL Server should not be emitting
ORDER BY or GROUP BY on a simple label name at all; when in fact,
we had forgotten that 0.9 was already emitting ORDER BY on a simple
label name for all backends, as described in :ref:`migration_1068`,
as 1.0 had rewritten this logic as part of :ticket:`2992`.

In 1.0.2, the bug is fixed both that SQL Server, Firebird and others
will again emit ORDER BY on a simple label name when passed a
:class:`.Label` construct that is expressed in the columns clause,
and no backend will emit GROUP BY on a simple label name in this case,
as even Postgresql can't reliably do GROUP BY on a simple name
in every case.
fixes #3338, fixes #3385

2 files changed, 14 insertions, 3 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 6ee4053a7..a178ed99a 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -3724,6 +3724,16 @@ def _literal_as_label_reference(element):
     elif hasattr(element, '__clause_element__'):
         element = element.__clause_element__()
 
+    return _literal_as_text(element)
+
+
+def _literal_and_labels_as_label_reference(element):
+    if isinstance(element, util.string_types):
+        return _textual_label_reference(element)
+
+    elif hasattr(element, '__clause_element__'):
+        element = element.__clause_element__()
+
     if isinstance(element, ColumnElement) and \
             element._order_by_label_element is not None:
         return _label_reference(element)
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index 7d8c885ae..245c54817 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -16,7 +16,7 @@ from .elements import _clone, \
     _literal_as_text, _interpret_as_column_or_from, _expand_cloned,\
     _select_iterables, _anonymous_label, _clause_element_as_expr,\
     _cloned_intersection, _cloned_difference, True_, \
-    _literal_as_label_reference
+    _literal_as_label_reference, _literal_and_labels_as_label_reference
 from .base import Immutable, Executable, _generative, \
     ColumnCollection, ColumnSet, _from_objects, Generative
 from . import type_api
@@ -1723,7 +1723,7 @@ class GenerativeSelect(SelectBase):
         if order_by is not None:
             self._order_by_clause = ClauseList(
                 *util.to_list(order_by),
-                _literal_as_text=_literal_as_label_reference)
+                _literal_as_text=_literal_and_labels_as_label_reference)
         if group_by is not None:
             self._group_by_clause = ClauseList(
                 *util.to_list(group_by),
@@ -1912,7 +1912,8 @@ class GenerativeSelect(SelectBase):
             if getattr(self, '_order_by_clause', None) is not None:
                 clauses = list(self._order_by_clause) + list(clauses)
             self._order_by_clause = ClauseList(
-                *clauses, _literal_as_text=_literal_as_label_reference)
+                *clauses,
+                _literal_as_text=_literal_and_labels_as_label_reference)
 
     def append_group_by(self, *clauses):
         """Append the given GROUP BY criterion applied to this selectable.