OCP-1Z0-051 补充题库 第13题 MERGE INTO语句

一、原题

Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables:



Which MERGE statement is valid?
A.

MERGE INTO new_employees c

USING employees e

ON (c.employee_id = e.employee_id)

WHEN MATCHED THEN

  UPDATE SET name = e.first_name || ',' || e.last_name

WHEN NOT MATCHED THEN

  INSERT value S

    (e.employee_id,

     e.first_name || ',

' || e.last_name);
B.

MERGE new_employees c

USING employees e

ON (c.employee_id = e.employee_id)

WHEN EXISTS THEN UPDATE SET name = e.first_name || ',' || e.last_name

WHEN NOT MATCHED THEN

  INSERT

  valueS

    (e.employee_id,

     e.first_name || ',

' || e.last_name);

C.

MERGE INTO new_employees c USING employees e

ON (c.employee_id = e.employee_id)

WHEN EXISTS THEN UPDATE SET name = e.first_name || ',' || e.last_name

WHEN NOT MATCHED THEN

  INSERT value S

    (e.employee_id,

     e.first_name || ',

' || e.last_name);

D.

MERGE new_employees c FROM employees e

ON (c.employee_id = e.employee_id)

WHEN MATCHED THEN

  UPDATE SET name = e.first_name || ',' || e.last_name

WHEN NOT MATCHED THEN

  INSERT INTO new_employees

  valueS

    (e.employee_id,

     e.first_name || ',

' || e.last_name);

答案: A

二、题目翻译

下面是EMPLOYEES和NEW_EMPLOYEES表的结构:

哪一个merge语句是有效的?

三、题目解析

A选项正确。

B选项和D选项不正确，merge into语法不正确，into关键字都没有。

C选项不正确，语法错误，WHEN EXISTS THEN，应该是 WHEN MATCHED THEN。