#进阶3 排序查询
SELECT * FROM employees;/*
select 查询列表
from 表
【where 筛选条件】
order by 排序列表【 asc|desc】
*/
#查询员工信息,要求工资从高到底
SELECT * FROM employees ORDER BY salary DESC;#从高到底
SELECT * FROM employees ORDER BY salary;#从低到高,默认升序
SELECT * FROM employees ORDER BY salary ASC;#从低到高
#查询部门编号>=90的员工信息,按入职时间的先后顺序进行排序[添加筛选条件]
SELECT
*
FROM
employees
WHERE department_id >=90
ORDER BY hiredate;
#按年薪的高低显示员工的信息和年薪【按表达式排序】
SELECT
*,salary*12*(1+IFNULL(commission_pct,0)) 年薪
FROM
employees
ORDER BY salary*12*(1+IFNULL(commission_pct,0));
#按别名排序
SELECT
*,salary*12*(1+IFNULL(commission_pct,0)) 年薪
FROM
employees
ORDER BY 年薪;
#按姓名长度显示员工的姓名和工资【按函数排序】
SELECT LENGTH(last_name) 字节长度,last_name,salary
FROM employees
ORDER BY LENGTH(last_name) DESC;
#查询员工信息,要求先按工资排序,再按员工编号排序【按多个字段排序】
SELECT
*
FROM
employees
ORDER BY salary ASC,employee_id DESC;
#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
SELECT last_name,department_id,salary*12*(1+IFNULL(commission_pct,0)) 年薪
FROM employees
ORDER BY 年薪 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
SELECT last_name,salary
FROM employees
WHERE salary NOT BETWEEN 8000 AND 17000
ORDER BY salary DESC;
#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 *,LENGTH(email)
FROM employees
WHERE email LIKE '%e%'
ORDER BY LENGTH(email) DESC,department_id ASC;