OCP-1Z0-051-題目解析-第40題

40. View the Exhibit to examine the description for the SALES and PRODUCTS tables. 
You want to create a SALE_PROD view  by executing the following SQL statement: 

CREATE VIEW sale_prod 
AS SELECT p.prod_id, cust_id, SUM(quantity_sold) "Quantity" , SUM(prod_list_price) "Price"     
FROM products p, sales s    
WHERE p.prod_id=s.prod_id 
GROUP BY p.prod_id, cust_id; 

Which statement is true regarding the execution of the  above statement? 
A. The view will be created and you can perform DML operations on the view. 
B. The view will be created but no DML operations will be allowed on the view. 
C. The view will not be created because the join statements are not allowed for creating a  view. 
D. The view will not be created because the  GROUP BY clause is not allowed for creating a  view. 


Answer: B 


A：視圖能被創建，並且能執行DML操作（錯誤，創建視圖語句中含有group by子句，爲複雜視圖，不可執行DML操作）
B：視圖被創建，但不能執行DML操作（正確）
C：視圖不能被創建，因爲join語句不允許使用在創建視圖中（錯誤，創建視圖可以使用多表）
D：視圖不能被創建，因爲group by子句不能使用在創建視圖中（錯誤，使用group by 創建的是複雜視圖）