OCP-1Z0-051 第16题 Q操作符的用法

一、原题

Evaluate the following query:
SQL> SELECT promo_name  q'{'s start date was }'  promo_begin_date
            AS "Promotion Launches"
     FROM promotions;
What would be the outcome of the above query?
A. It produces an error because flower braces have been used.
B. It produces an error because the data  types are not matching.
C. It executes successfully and introduces an  's at the end of each promo_name in the output.
D. It executes successfully and displays the literal " {'s start date was } " for each row in the output

答案：C

二、题目翻译

下面的查询语句：
SQL> SELECT promo_name  q'{'s start date was }'  promo_begin_date
            AS "Promotion Launches"
     FROM promotions;
上面的查询语句输出什么内容？
A. 它产生一个错误，因为花括号被使用。
B. 它产生一个错误，因为数据类型不匹配。
C. 它会执行成功，并且每一个promo_name后面会输出一个’s.
D. 它会执行成功，并且每一行会显示" {'s start date was } "。

三、题目解析
    关于Q操作符的用法，详见：
        http://blog.csdn.net/holly2008/article/details/23214389