1z0-071 Oracle Database 12c SQL 第25题 RIGHT OUTER JOIN和LEFT OUTER JOIN
Q25. Examine the structure of the EMPLOYEES table.
Name Null? Type
-—————- —– —— ——
EMPLOYEE_ID NOT NULL NUMBER(6)
FIRST_NAME VARCHAR2(20)
LAST_NAME NOT NULL VARCHAR2(25)
EMAIL NOT NULL VARCHAR2(25)
PHONE NUMBER VARCHAR2(20)
HIRE_DATE NOT NULL DATE
JOB_ID NOT NULL VARCHAR2(10)
SALARY NUMBER(8,2)
COMMISSION_PCT NUMBER(2,2)
MANAGER_ID NUMBER(6)
DEPARTMENT_ID NUMBER(4)
There is a parent/child relationship between EMPLOYEE_ID and MANAGER_ID.
You want to display the last names and manager IDs of employees who work for the same manager as the employee whose EMPLOYEE_ID is 123.
Which query provides the correct output?
A. SELECT e.last_name, m.manager_id
FROM employees e RIGHT OUTER JOIN employees m on (e.manager_id = m.employee_id)
AND e.employee_id = 123;
B. SELECT e.last_name, m.manager_id
FROM employees e RIGHT OUTER JOIN employees m on (e.employee_id = m.manager_id)
WHERE e.employee_id = 123;
C. SELECT e.last_name, e.manager_id
FROM employees e RIGHT OUTER JOIN employees m on (e.employee_id = m.employee_id)
WHERE e.employee_id = 123;
D. SELECT m.last_name, e.manager_id
FROM employees e LEFT OUTER JOIN employees m on (e.manager_id = m.manager_id)
Name Null? Type
-—————- —– —— ——
EMPLOYEE_ID NOT NULL NUMBER(6)
FIRST_NAME VARCHAR2(20)
LAST_NAME NOT NULL VARCHAR2(25)
EMAIL NOT NULL VARCHAR2(25)
PHONE NUMBER VARCHAR2(20)
HIRE_DATE NOT NULL DATE
JOB_ID NOT NULL VARCHAR2(10)
SALARY NUMBER(8,2)
COMMISSION_PCT NUMBER(2,2)
MANAGER_ID NUMBER(6)
DEPARTMENT_ID NUMBER(4)
There is a parent/child relationship between EMPLOYEE_ID and MANAGER_ID.
You want to display the last names and manager IDs of employees who work for the same manager as the employee whose EMPLOYEE_ID is 123.
Which query provides the correct output?
A. SELECT e.last_name, m.manager_id
FROM employees e RIGHT OUTER JOIN employees m on (e.manager_id = m.employee_id)
AND e.employee_id = 123;
B. SELECT e.last_name, m.manager_id
FROM employees e RIGHT OUTER JOIN employees m on (e.employee_id = m.manager_id)
WHERE e.employee_id = 123;
C. SELECT e.last_name, e.manager_id
FROM employees e RIGHT OUTER JOIN employees m on (e.employee_id = m.employee_id)
WHERE e.employee_id = 123;
D. SELECT m.last_name, e.manager_id
FROM employees e LEFT OUTER JOIN employees m on (e.manager_id = m.manager_id)
WHERE e.employee_id = 123;
Correct Answer: D