OCP-1Z0-051-V9.02-123题

123. View the Exhibits  and examine the structures of the PRODUCTS, SALES,  and CUSTOMERS

tables.

You need to generate a report that gives details of the customer's last name, name of the product,  and

the quantity sold for all customers in ' Tokyo' .

Which two queries give the required result? (Choose two.)

A. SELECT c.cust_last_name,p.prod_name, s.quantity_sold

FROM sales s JOIN products p

USING(prod_id)

JOIN customers c

USING(cust_id)

WHERE c.cust_city='Tokyo';

B. SELECT c.cust_last_name, p.prod_name, s.quantity_sold

FROM products p JOIN sales s JOIN customers c  

ON(p.prod_id=s.prod_id)

ON(s.cust_id=c.cust_id)

WHERE c.cust_city='Tokyo';

C. SELECT c.cust_last_name, p.prod_name, s.quantity_sold

FROM products p JOIN sales s

ON(p.prod_id=s.prod_id)

JOIN customers c

ON(s.cust_id=c.cust_id)

AND c.cust_city='Tokyo';

D. SELECT c.cust_id,c.cust_last_name,p.prod_id, p.prod_name, s.quantity_sold 

FROM products p JOIN sales s

USING(prod_id)

JOIN customers c

USING(cust_id)

WHERE c.cust_city='Tokyo';

Answer: AC
答案解析:
B语法错误
D中p.prod_id不应该跟限定的表别名。
不要对USING子句中使用的列加以限定。
USING子句中引用的那些列不能在SQL 语句的任何位置使用限定词(表名或别名)
如果在SQL 语句的另一个位置使用了同一列,则不要对其设置别名。
原文地址:https://www.cnblogs.com/hzcya1995/p/13316867.html