OCP-1Z0-051 第114题 HAVING，GROUP BY子句的应用

一、原题

View the Exhibit and examine the structure of the SALES table.

The following query is written to retrieve all those product ID s from the SALES table that have more than 55000 sold and have been ordered more than 10 times.
SQL> SELECT prod_id
              FROM sales
           WHERE quantity_sold > 55000 AND COUNT(*)>10
     GROUP BY prod_id
          HAVING COUNT(*)>10;
Which statement is true regarding this SQL statement?
A. It executes successfully and generates the required result.
B. It produces an error because COUNT(*) should be specified in the SELECT clause also.
C. It produces an error because COUNT(*) should be only in the HAVING clause and not in the WHERE clause.
D. It executes successfully but produces no result because COUNT(prod_id) should be used instead of COUNT(*).

答案：C

二、题目翻译

查看SALES表的结构：
下面的查询用于检索那些售出了超过55000台,并且已被定购超过10次的所有产品ID。
关于查询语句的描述，正确的是？
A.执行成功,并给出正确结果。
B.报错，因为COUNT(*)也应该指定到SELECT子句中。
C.报错，因为COUNT(*)只能用在HAVING子句中，不能在WHERE子句中。
D.执行成功，但是没有返回结果，因为COUNT(prod_id)应该用COUNT(*)代替。