View the Exhibit and examine the data in the table.
You need to generate a report that displays the IDs of all products in the COSTS table whose unit price is at least 25% more than the unit cost. The details should be displayed in the descending order of 25% of the unit cost.
You issue the following query:
SQL>SELECT prod_id
FROM costs
WHERE unit_price >= unit_cost * 1.25
ORDER BY unit_cost * 0.25 DESC;
Which statement is true regarding the above query?
A. It executes and produces the required result.
B. It produces an error because an expression cannot be used in the ORDER BY clause.
C. It produces an error because the DESC option cannot be used with an expression in the ORDER BY clause.
D. It produces an error because the expression in the ORDER BY clause should also be specified in the SELECT clause.
答案：A
二、题目翻译
查看COSTS 表的数据
要生成一个报表，显示COSTS表中所有产品ID，产品的unit price至少要比unit cost多25%，按unit cost的25%降序显示产品信息。
执行下面的查询
下面关于上面的查询的描述，哪句话是正确的？
A.获取所需的结果。
B.报错，因为表达式不能用在ORDER BY子句中。
C.报错，因为DESC不能用在ORDER BY的表达式中。
D.报错，因为ORDER BY子句中的表达式也应该在SELECT子句中。
三、题目解析
B选项不正确，表达式可以出现在ORDER BY子句中。
C选项不正确，DESC就是用在ORDER BY子句中按降序排序的。
D选项不正确，是SELECT子句中的表达式，应该出现在GROUP BY中，而不是ORDER BY。