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
单项选择题 What is true about sequences?（）
单项选择题 In which scenario would index be most useful?（）
单项选择题 The EMPLOYEES table contains these columns: EMPLOYEE_ID NUMBER(4) LAST_NAME VARCHAR2 (25) JOB_ID VARCHAR2(10) You want to search for strings that contain SA_ in the JOB_ID column. Which SQL statement do you use?（）