36.choose the best answer
View the Exhibits and examine the structures of the PRODUCTS, SALES, and CUSTOMERS tables.
You issue the following query:
SQL>SELECT p.prod_id,prod_name,prod_list_price,
quantity_sold,cust_last_name
FROM products p NATURAL JOIN sales s NATURAL JOIN customers c
WHERE prod_id =148;
Which statement is true regarding the outcome of this query?
A) It executes successfully.
B) It produces an error because a column used in the NATURAL join cannot have a qualifier.
C) It produces an error because all columns used in the NATURAL join should have a qualifier.
D) It produces an error because the NATURAL join can be used only with two tables.
Answer：B
(解析：执行该语句时返回错误：
SELECT p.prod_id,prod_name,prod_list_price,
*
第 1 行出现错误:
ORA-25155: NATURAL 联接中使用的列不能有限定词
)
阅读(785) | 评论(0) | 转发(0) |
