Though the documentation for the NUMBER function stated “Use the NUMBER function only in a select list or a SET clause of an UPDATE statement A syntax error is generated if you use NUMBER in any other type of statement,” it was requested that the statements be listed. This section now contains the following note:
A syntax error is generated if you use NUMBER in a DELETE statement, WHERE clause, HAVING clause, ORDER BY clause, subquery, query involving aggregation, any constraint, GROUP BY, DISTINCT, a query containing UNION ALL, or a derived table.