A. You want to identify the most senior employee in the……

多项选择题Which three are true regarding the use of outer joins?（）

A. You cannot use IN operator in a condition that involves an outerjoin.
B. You use (+) on both sides of the WHERE condition to perform an outerjoin.
C. You use (*) on both sides of the WHERE condition to perform an outerjoin.
D. You use an outerjoin to see only the rows that do not meet the join condition.
E. In the WHERE condition, you use (+) following the name of the column in the table without matching rows, to perform an outerjoin.
F. You cannot link a condition that is involved in an outerjoin to another condition by using the OR operator.

单项选择题Exhibit Examine the data in the EMPLOYEES and DEPARTMENTS tables. You want to retrieve all employees last names, along with their managers last names and their department names. Which query would you use?（）

A. SELECT last_name, manager_id, department_name FROM employees e FULL OUTER JOIN department d ON (e.department_id = d.department_id);
B. SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on ( e.managaer_id = m.employee_id) LEFT OUTER JOIN department d ON (e.department_id = d.department_id);
C. SELECT e.last_name, m.last_name, department_name FROM employees e RIGT OUTER JOIN employees m on ( e.manager_id = m.employee_id) FULL OUTER JOIN department d ON (e.department_id = d.department_id);
D. SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on ( e.manager_id = m.employee_id) RIGT OUTER JOIN department d ON (e.department_id = d.department_id);
E. SELECT e.last_name, m.last_name, department_name FROM employees e RIGHT OUTER JOIN employees m on ( e.manager_id = m.employee_id) RIGHT OUTER JOIN departments d ON (e.department_id = d.department_id)
F. SELECT last_name, manager_id, department_name FROM employees e JOIN department d ON (e.department_id = d.department_id);

单项选择题Which statement creates a new user?（）

A. CREATE USER susan;
B. CREATE OR REPLACE USER susan;
C. CREATE NEW USER susan    DEFAULT;
D. CREATE USER susan    IDENTIFIED BY blue;
E. CREATE NEW USER susan   IDENTIFIED by blue;
F. CREATE OR REPLACE USER susan   IDENTIFIED BY blue;

单项选择题You need to change the definition of an existing table. The COMMERCIALS table needs its DESCRIPTION column changed to hold varying length characters up to 2000 bytes. The column can currently hold 1000 bytes per value. The table contains 20000 rows. Which statement is valid?（）

A. ALTER TABLE commercials   MODIFY (description CHAR2(2000));
B. ALTER TABLE commercials   CHANGE (description CHAR2(2000));
C. ALTER TABLE commercials   CHANGE (description VARCHAR2(2000));
D. ALTER TABLE commercials   MODIFY (description VARCHAR2(2000));
E. You cannot increase the size of a column if the table has rows.

单项选择题What does the TRUNCATE statement do?（）

A. Removes the table
B. Removes all rows from a table
C. Shortens the table to 10 rows
D. Removes all columns from a table
E. Removes foreign keys from a table