• OCP-1Z0-051-V9.02-162题


    162. View the Exhibit and examine the structure of the PRODUCTS, SALES, and SALE_SUMMARY

    tables.

    SALE_VW   is a view created using the following command :

    SQL>CREATE VIEW sale_vw AS

    SELECT prod_id, SUM(quantity_sold) QTY_SOLD

    FROM sales GROUP BY prod_id;

    You issue the following command to add a row to the  SALE_SUMMARY   table :

    SQL>INSERT INTO sale_summary

    SELECT prod_id, prod_name, qty_sold FROM sale_vw JOIN products  

    USING (prod_id) WHERE prod_id = 16;

    What is the outcome? 

    A. It executes successfully.

    B. It gives an error because a complex view cannot be used to add data into the SALE_SUMMARY table.

    C. It gives an error because the column names in the subquery and the SALE_SUMMARY table do not

    match.

    D. It gives an error because the number of columns to be inserted does not match with the number of

    columns in the SALE_SUMMARY table.

    Answer: D

    答案解析:

    参考:http://blog.csdn.net/rlhua/article/details/12885143

    由于列的数量不匹配造成的,如果数量一致,会执行成功。

     带有子查询的INSERT语句,勿使用VALUES子句,并且使INSERT子句中的列数与子查询中的列数匹配。

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  • 原文地址:https://www.cnblogs.com/hzcya1995/p/13316840.html
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