Q: 10 Click the Exhibit button and examine the data from the EMP table.
The COMMISSION column shows the monthly commission earned by the employee.
Which three tasks would require subqueries or joins in order to be performed in a single step? (Choose
three.)
中间有照片，但是传不上来啊！
A. deleting the records of employees who do not earn commission
B. increasing the commission of employee 3 by the average commission earned in department 20
C. finding the number of employees who do NOT earn commission and are working for department 20
D. inserting into the table a new employee 10 who works for department 20 and earns a commission that is
equal to the commission earned by employee 3
E. creating a table called COMMISSION that has the same structure and data as the columns EMP_ID and
COMMISSION of the EMP table
F. decreasing the commission by 150 for the employees who are working in department 30 and earning a
commission of more than 800
Answer: B, D, E
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看不到图,不好判断?
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我来解释下 请指教
题目：
Q: 10 Click the Exhibit button and examine the data from the EMP table.
The COMMISSION column shows the monthly commission earned by the employee.
Which three tasks would require subqueries or joins in order to be performed in a single step? (Choose
three.)
点击执行按钮查询emp表的记录
commission 列显示的是雇员每个月的佣金
选择 需要子查询或者连接查询的3项 目的是完成独立的操作
下面说说选项
A. deleting the records of employees who do not earn commission
B. increasing the commission of employee 3 by the average commission earned in department 20
C. finding the number of employees who do NOT earn commission and are working for department 20
D. inserting into the table a new employee 10 who works for department 20 and earns a commission that is
equal to the commission earned by employee 3
E. creating a table called COMMISSION that has the same structure and data as the columns EMP_ID and
COMMISSION of the EMP table
F. decreasing the commission by 150 for the employees who are working in department 30 and earning a
commission of more than 800
A 删除佣金为空的雇员信息 所以不选
B 增加雇员3的佣金 参照部门20的平均工资 所以这里要来个子查询 求出部门20的平均工资 所以选择
C 查找出为部门20工作的员工并且佣金为空的 不选择
D 添加一条员工工号为10 部门号为 20 的记录 并且该员工的佣金和员工3相等 用到子查询 即选择
E 创建一个表commission 这个表和emp表的emp_id和commission结构和数据类型一致 哪么这个也要选择 用到子查询
F 降低为部门30工作的员工并且佣金超过800的员工佣金 0.15 不需要子查询 所以不选择
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B 是平均佣金