OCP-1Z0-051 补充题库 第4题 聚合函数的使用
发布时间：2020-12-13 23:01:52 所属栏目：百科 来源：网络整理
导读：一、原题 See the Exhibit and examine the structure and data in the INVOICE table: Exhibit: Which two SQL statements would executes successfully? (Choose two.) A. SELECT MAX(inv_date),MIN(cust_id) FROM invoice; B. SELECT MAX(AVG(SYSDATE - i
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一、原题
See the Exhibit and examine the structure and data in the INVOICE table:
Exhibit: Which two SQL statements would executes successfully? (Choose two.) A. SELECT MAX(inv_date),MIN(cust_id) FROM invoice; B. SELECT MAX(AVG(SYSDATE - inv_date)) FROM invoice; C. SELECT AVG(inv_date) FROM invoice; D. SELECT AVG(inv_date - SYSDATE),AVG(inv_amt) FROM invoice; 答案: A,D 二、题目翻译
看下面INVOICE表的结构：
哪两个SQL会执行成功（选择两项）? 三、题目解析
B选项不正确，SYSDATE - inv_date的结果是数字，这里AVG的结果就只有一条记录了，再求MAX，就没意义了，这句会报错。 C选面不正确，inv_date是日期类型，AVG求日期的平均值，会报错。
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