Listing A

CREATE OR REPLACE VIEW order_data_view AS
   SELECT 
       TO_CHAR(o.order_date,'yyyy') order_year,
       o.order_mode,
       SUM(o.order_total) order_total
   FROM
     orders o 
   GROUP BY order_mode, 
            TO_CHAR(o.order_date,'yyyy')
   ORDER BY
       order_year, o.order_mode
/


SQL> @model_a

View created.

SQL> SELECT * FROM order_data_view;

ORDER_YEAR      ORDER_MO ORDER_TOTAL                                            
--------------- -------- -----------                                            
1990            direct       61655.7                                            
1996            direct        5546.6                                            
1997            direct           310                                            
1998            direct      309929.8                                            
1998            online      100056.6                                            
1999            direct     1274078.8                                            
1999            online     1271019.5                                            
2000            direct      252108.3                                            
2000            online      393349.4                                            

9 rows selected.

SQL>