单项选择题
A. Immediately after the SELECT clause
B. Before the WHERE clause
C. Before the FROM clause
D. After the ORDER BY clause
E. After the WHERE clause
多项选择题 Examine the SQL statements that creates ORDERS table: For which columns would an index be automatically created when you execute the above SQL statement? （）
单项选择题 Examine the data of the EMPLOYEES table. EMPLOYEES (EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID) EMP_NAME DEPT_ID MGR_ID JOB_ID SALARY EMPLOYEE_ID 101 Smith 20 120 SA_REP 4000 102 Martin 10 105 CLERK 2500 103 Chris 20 120 IT_ADMIN 4200 104 John 30 108 HR_CLERK 2500 105 Diana 30 108 HR_MGR 5000 106 Bryan 40 110 AD_ASST 3000 108 Jennifer 30 110 HR_DIR 6500 110 Bob 40 EX_DIR 8000 120 Ravi 20 110 SA_DIR 6500 Which statement lists the ID, name, and salary of the employee, and the ID and name of the employees manager, for all the employees who have a manager and earn more than 4000?（）
单项选择题 Which statement explicitly names a constraint?（）