单项选择题
A. SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP;
B. SELECT ROUND(hire_date) FROM EMP;
C. SELECT sysdate-hire_date FROM EMP;
D. SELECT TO_NUMBER(hire_date + 7) FROM EMP;
多项选择题 When should you create a role?（）
单项选择题 Which clause would you use in a SELECT statement to limit the display to those employees whose salary is greater then 5000?（）
单项选择题 Examine this statement: SELECT student_id, gpa FROM student_grades WHERE gpa >&&value; You run the statement once, and when prompted you enter a value of 2.0. A report is produced. What happens when you run the statement a second time?（）