【OCP-12c】2019年CUUG OCP 071考试题库(80题)
80、View the exhibit and examine the structure in ORDERS and ORDER_ITEMS tables.
You need to create a view that displays the ORDER_ID,ORDER_DATE,and the total number of items in each order. Which CREATE VIEW statement would create the views successfully? A . AS SELECT o.order_id,o.order_date,COUNT (i.line_item_id) FROM orders o JOIN order_items i ON (o.order_id = i.order_id) GROUP BY o.order_id,o.order_date; B. CREATE OR REPLACE VIEW ord_vu (order_id,order_date) AS SELECT o.order_id,COUNT (i.line_item_id) "NO OF ITEMS" FROM orders o JOIN order_items i ON (o.order_id = i.order_id) GROUP BY o.order_id, o.order_date; C. CREATE OR REPLACE VIEW ord_vu AS SELECT o.order_id,COUNT (i.line_item_id) "NO OF ITEMS" FROM orders o JOIN order_items i ON (o.order_id = i.order_id) GROUP BY o.order_id,o.order_date; D. CREATE OR REPLACE VIEW ord_vu AS SELECT o.order_id,COUNT (i.line_item_id) || "NO OF ITEMS" FROM orders o JOIN order_items i ON (o.order_id = i.order_id) GROUP BY o.order_id,o.order_date WHITH CHECK OPTION; Correct Answer: C Section: (none) Explanation:A答案会报错:ORA-00998: 必须使用列别名命名此表达式,缺少一个别名;B答案视图缺少一个列名,如果加上"NO OF ITEMS"就是正确的。 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |