ORDER BY clause - is used to order rows returned by the statement. Without an order_by_clause, no guarantee exists that
the same query executed more than once will retrieve rows in the same order.
Restrictions on the order_by_clause:
w If you have specified the DISTINCT operator in this statement, this clause cannot refer to columns unless they appear
in the select list.
w An order_by_clause can contain no more than 255 expressions.
w You cannot order by a LOB column, nested table, or varray.