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  • 【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, o.order_date, 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, o.order_date, 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, o.order_date, 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。

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  • 原文地址:https://www.cnblogs.com/cnblogs5359/p/10551948.html
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