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047-117

原创 Linux操作系统 作者:jbymy2000 时间:2012-03-19 09:26:48 0 删除 编辑
117. View the Exhibit and examine the structure of ORDERS and CUSTOMERS
tables.Evaluate the following UPDATE statement:
UPDATE (SELECT order_date, order_total, customer_id FROM orders)SET
order_date = '22mar2007' WHERE customer_id =(SELECT customer_id
FROM customers WHERE cust_last_name = 'Roberts' AND credit_limit = 600);
Which statement is true regarding the execution of the above UPDATE
statement?
A. It would not execute because two tables cannot be used in a single UPDATE
statement.
B. It would execute and restrict modifications to only the columns specified
in the SELECT statement.
C. It would not execute because a subquery cannot be used in the WHERE clause
of an UPDATE statement.
D.It would not execute because the SELECT statement cannot be used in place
of the table name.
Answer: B
Restrict:限制

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