| ERROR | MV with UNION ALL in a view must match the views SELECT list |
| CAUSE | If a materialized view has a view whose definition involves a UNION ALL query, then the materialized views select list must match the underlying views select list exactly. It must not have any expressions and must not have add/drop/reorder columns from the underlying view. |
| ACTION | Use select * when defining a materialized view with a UNION ALL in a view. |