1Z0-051-13题

13. View the Exhibit and examine the structure of the PRODUCTS table.
You need to generate a report in the following format:
CATEGORIES
5MP Digital Photo Camera's category is Photo
Y Box's category is Electronics
Envoy Ambassador's category is Hardware
Which two queries would give the required output? (Choose two.) 

A. SELECT prod_name   q'''s category is '   prod_category CATEGORIES
FROM products;
B. SELECT prod_name   q'['s ]'category is '   prod_category CATEGORIES
FROM products;
C. SELECT prod_name   q'\'s\'   ' category is '   prod_category CATEGORIES
FROM products;
D. SELECT prod_name   q'<'s >'   'category is '   prod_category CATEGORIES
FROM products;
Answer: CD

另外Oracle还提供了一个Q-quote的表达式，来简化SQL或PLSQL中字符串的表示，其格式为q'[Camera's category is Photo]',输出为方括号中的原始字符串格式，其中方括号可以更换为其他的任意一对特殊符号，但必须是成对出现的，不可为q'[Camera's category is Photo|'。
如：
SQL> select q'[Camera's category is Photo]' name from dual;

NAME
--------------------------
Camera's category is Photo

SQL> select q'|Camera's category is 'Photo'|' name from dual;

NAME
----------------------------
Camera's category is 'Photo'

A：错误， is后面应该是两个单引号，正确的为
SELECT prod_name || q'''s category is ''|| prod_category CATEGORIES
FROM products;
B:错误，category 前面少了一个',正确的为
SELECT prod_name || q'['s ]'||'category is '||prod_category CATEGORIES FROM products;