Merge "Add additional support to honor _proxy_key in Core selects"

3 files changed, 25 insertions, 7 deletions

diff --git a/lib/sqlalchemy/orm/context.py b/lib/sqlalchemy/orm/context.py
index 26e35b66e..0af3fd6af 100644
--- a/lib/sqlalchemy/orm/context.py
+++ b/lib/sqlalchemy/orm/context.py
@@ -2890,7 +2890,7 @@ class _ORMColumnEntity(_ColumnEntity):
                 ezero._adapter if ezero.is_aliased_class else None,
             )
 
-        if column._annotations:
+        if column._annotations and not column._expression_label:
             # annotated columns perform more slowly in compiler and
             # result due to the __eq__() method, so use deannotated
             column = column._deannotate()
diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 73311f110..173314abe 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -887,6 +887,21 @@ class ColumnElement(
         else:
             return getattr(self, "name", "_no_label")
 
+    @util.memoized_property
+    def _expression_label(self):
+        """a suggested label to use in the case that the column has no name,
+        which should be used if possible as the explicit 'AS <label>'
+        where this expression would normally have an anon label.
+
+        """
+
+        if getattr(self, "name", None) is not None:
+            return None
+        elif self._annotations and "proxy_key" in self._annotations:
+            return self._annotations["proxy_key"]
+        else:
+            return None
+
     def _make_proxy(
         self, selectable, name=None, key=None, name_is_truncatable=False, **kw
     ):
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index 0092fe094..235c74ea7 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -5815,14 +5815,17 @@ class Select(
                         repeated = c._anon_name_label in names
                         names[c._anon_name_label] = c
                         return (None, c, repeated)
+                    else:
+                        name = effective_name = c._label
                 elif getattr(c, "name", None) is None:
                     # this is a scalar_select().  need to improve this case
-                    repeated = c._anon_name_label in names
-                    names[c._anon_name_label] = c
-                    return (None, c, repeated)
-
-                if use_tablename_labels:
-                    name = effective_name = c._label
+                    expr_label = c._expression_label
+                    if expr_label is None:
+                        repeated = c._anon_name_label in names
+                        names[c._anon_name_label] = c
+                        return (None, c, repeated)
+                    else:
+                        name = effective_name = expr_label
                 else:
                     name = None
                     effective_name = c.name