#第五章、练习题
SELECT * FROM employees;

#1、查询员工的姓名和部门号和年薪，按年薪降序，按姓名升序显示
SELECT last_name,department_id,salary*12*(1+IFNULL(commission_pct,0)) ySalary
FROM employees
ORDER BY ySalary DESC,last_name ASC;

#2、选择工资不在8000到17000的员工的姓名和工资，按工资降序，显示第21到40位置的数据
SELECT last_name,salary
FROM employees
WHERE salary NOT BETWEEN 8000 AND 17000
ORDER BY salary DESC
LIMIT 20,20;

#3、查询邮箱中包含e的员工信息，并先按邮箱的字节数降序，再按部门号升序
SELECT employee_id,last_name,email,department_id
FROM employees
#WHERE email LIKE '%e%'
WHERE email REGEXP '[e]'
ORDER BY LENGTH(email) DESC, department_id ASC;