多项选择题
A.You have too many tables.
B.Your tables are too long.
C.Your tables have difficult names.
D.You want to work on your own tables.
E.You want to use another schema's tables.
F.You have too many columns in your tables.
单项选择题 What is necessary for your query on an existing view to execute successfully?（）
单项选择题 You need to create a view EMP_VU. The view should allow the users tomanipulate the records of only the employees that are working for departments 10 or 20. Which SQL statement would you use to create the view EMP_VU?（）
单项选择题 Evaluate this SQL statement: SELECT e.employee_id, (.15* e.salary) + (.5 * e.commission_pct) + (s.sales_amount * (.35 * e.bonus)) AS CALC_VALUE FROM employees e, sales s WHERE e.employee_id = s.emp_id; What will happen if you remove all the parentheses from the calculation?（）