OCP-1Z0-051-V9 02-166题

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166. View the Exhibit and examine the structures of the EMPLOYEES and DEPARTMENTS tables.

You want to update the EMPLOYEES table as follows:4 ? 4;

-Update only those employees who work in Boston or Seattle (locations 2900 and 2700).

-Set department_id for these employees to the department_id corresponding to London (location_id

2100).

-Set the employees' salary in location_id 2100 to 1.1 times the average salary of their department.

-Set the employees' commission in location_id 2100 to 1.5 times the average commission of their

department.

You issue the following command:

SQL>UPDATE employees     

SET department_id =     

(SELECT department_id             

FROM departments             

WHERE location_id = 2100),         

(salary, commission) =         

(SELECT 1.1*AVG(salary), 1.5*AVG(commission)           

FROM employees, departments           

WHERE departments.location_id IN(2900,2700,2100))         

WHERE department_id IN         

(SELECT department_id           

FROM departments           

WHERE location_id = 2900               

OR location_id = 2700)

What is the outcome?

 

 

A. It executes successfully and gives the correct result.

B. It executes successfully but does not give the correct result.

C. It generates an error because a subquery cannot have a join condition in an UPDATE statement.

D. It generates an error because multiple columns (SALARY, COMMISION) cannot be specified together

in an UPDATE statement.

Answer: B

 答案解析：

题意要求更新条件：

1.只更新那些在Boston或Seattle工作的employees（locations为2900或者2700）

2.设置这些employees的department_id为London（location_id 2100）对应的department_id

3.设置location_id 2100的employees' salary为他们部门的平均薪水的1.1倍

4.设置location_id 2100的employees' commission为他们部门的平均提成的1.5倍

UPDATE employees     

SET department_id =     

(SELECT department_id FROM departments WHERE location_id = 2100),         

(salary, commission) = (SELECT 1.1*AVG(salary), 1.5*AVG(commission)  FROM employees, departments           

WHERE departments.location_id IN(2900,2700,2100))         

WHERE department_id IN (SELECT department_id FROM departments WHERE location_id = 2900 OR location_id = 2700)

 

WHERE departments.location_id IN(2900,2700,2100))        应该使用部门ID进行关联。

 

           

分享一下我老师大神的人工智能教程。零基础！通俗易懂！风趣幽默！还带黄段子！希望你也加入到我们人工智能的队伍中来！https://blog.csdn.net/jiangjunshow