单项选择题
A. Selection, projection, join
B. Difference, projection, join
C. Selection, intersection, join
D. Intersection, projection, join
E. Difference, projection, product
单项选择题 You need to perform certain data manipulation operations through a view called EMP_DEPT_VU, which you previously created. You want to look at the definition of the view (the SELECT statement on which the view was create.) How do you obtain the definition of the view? （）
单项选择题 You need to display the last names of those employees who have the letter "A" as the second character in their names. Which SQL statement displays the required results? （）
单项选择题 Which operator can be used with a multiple-row subquery? （）