单项选择题
A.SELECT ename, salary*12 'Annual Salary' FROM employees;
B.SELECT ename, salary*12 "Annual Salary" FROM employees;
C.SELECT ename, salary*12 AS Annual Salary FROM employees;
D.SELECT ename, salary*12 AS INITCAP("ANNUAL SALARY") FROM employees
多项选择题 What are two reasons to create synonyms? （）
单项选择题 Click the Exhibit button and examine the data from the ORDERS and CUSTOMERS tables. Which SQL statement retrieves the order ID, customer ID, and order total for the orders that are placed on the same day that Martin placed his orders?（）
多项选择题 Click the Exhibit button and examine the data from the EMP table. The COMMISSION column shows the monthly commission earned by the employee. Which two tasks would require subqueries or joins in order to be performed in a single step? （）