16. 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.
Answer: C
题目解析：
A：会产生一个错误，由于使用的花括号（错误，该处的花括号是Q-quote的表达式）
B：会产生一个错误。由于数据类型不匹配（错误，无关选项）
C：会正确运行。而且在每个promo_name后面加入一个's(正确，这是一个Q-quote的表达式）
D: 会正确运行，而且在每行输出字符串{'s start date was }（错误）
关于这道题的具体解答參照第13题：http://blog.****.net/wjx515628/article/details/35278889