单项选择题
A.difference, projection, join
B.selection, projection, join
C.selection, intersection, join
D.intersection, projection, join
E.difference, projection, product
单项选择题 Which SQL statement generates the alias Annual Salary for the calculated column SALARY*12?（）
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?（）