Merging upstream version 15.0.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/sqlglot/optimizer/pushdown_projections.py b/sqlglot/optimizer/pushdown_projections.py
index 2e51117..be3ddb2 100644
--- a/sqlglot/optimizer/pushdown_projections.py
+++ b/sqlglot/optimizer/pushdown_projections.py
@@ -39,8 +39,9 @@ def pushdown_projections(expression, schema=None, remove_unused_selections=True)
     for scope in reversed(traverse_scope(expression)):
         parent_selections = referenced_columns.get(scope, {SELECT_ALL})
 
-        if scope.expression.args.get("distinct"):
-            # We can't remove columns SELECT DISTINCT nor UNION DISTINCT
+        if scope.expression.args.get("distinct") or scope.parent and scope.parent.pivots:
+            # We can't remove columns SELECT DISTINCT nor UNION DISTINCT. The same holds if
+            # we select from a pivoted source in the parent scope.
             parent_selections = {SELECT_ALL}
 
         if isinstance(scope.expression, exp.Union):
@@ -105,7 +106,9 @@ def _remove_unused_selections(scope, parent_selections, schema):
 
         for name in sorted(parent_selections):
             if name not in names:
-                new_selections.append(alias(exp.column(name, table=resolver.get_table(name)), name))
+                new_selections.append(
+                    alias(exp.column(name, table=resolver.get_table(name)), name, copy=False)
+                )
 
     # If there are no remaining selections, just select a single constant
     if not new_selections: