Merging upstream version 26.12.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

sqlglot/optimizer/merge_subqueries.py

@@ -129,8 +129,7 @@ def _mergeable(
     inner_select = inner_scope.expression.unnest()
 
     def _is_a_window_expression_in_unmergable_operation():
-        window_expressions = inner_select.find_all(exp.Window)
-        window_alias_names = {window.parent.alias_or_name for window in window_expressions}
+        window_aliases = {s.alias_or_name for s in inner_select.selects if s.find(exp.Window)}
         inner_select_name = from_or_join.alias_or_name
         unmergable_window_columns = [
             column
@@ -142,7 +141,7 @@ def _mergeable(
         window_expressions_in_unmergable = [
             column
             for column in unmergable_window_columns
-            if column.table == inner_select_name and column.name in window_alias_names
+            if column.table == inner_select_name and column.name in window_aliases
         ]
         return any(window_expressions_in_unmergable)
 

sqlglot/optimizer/pushdown_projections.py

@@ -4,6 +4,7 @@ from sqlglot import alias, exp
 from sqlglot.optimizer.qualify_columns import Resolver
 from sqlglot.optimizer.scope import Scope, traverse_scope
 from sqlglot.schema import ensure_schema
+from sqlglot.errors import OptimizeError
 
 # Sentinel value that means an outer query selecting ALL columns
 SELECT_ALL = object()
@@ -49,6 +50,10 @@ def pushdown_projections(expression, schema=None, remove_unused_selections=True)
 
         if isinstance(scope.expression, exp.SetOperation):
             left, right = scope.union_scopes
+            if len(left.expression.selects) != len(right.expression.selects):
+                scope_sql = scope.expression.sql()
+                raise OptimizeError(f"Invalid set operation due to column mismatch: {scope_sql}.")
+
             referenced_columns[left] = parent_selections
 
             if any(select.is_star for select in right.expression.selects):

sqlglot/optimizer/qualify_columns.py

@@ -272,7 +272,7 @@ def _expand_alias_refs(
     """
     expression = scope.expression
 
-    if not isinstance(expression, exp.Select):
+    if not isinstance(expression, exp.Select) or dialect == "oracle":
         return
 
     alias_to_expression: t.Dict[str, t.Tuple[exp.Expression, int]] = {}