本教程中所使用的数据库的建表语句都在“SQL教程——索引”这篇文章中，点击链接直达：索引&建表语句

摘要：本文主要SQL语句中order by的语法和使用

order by

orderby语法：

select 查询列表

from 表

【where筛选条件】

orderby排序列表【asc | desc 】

select * from employees order by salary desc;select * from employees order by salary asc;

select * from employees where department_id >= 90 order by hiredate asc;#按照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 bysalary * 12 * (1 + ifnull(commission_pct, 0)) desc;#按照年薪的高低显示员工的信息和年薪【按别名排序】select *, salary * 12 * (1 + ifnull(commission_pct, 0))年薪 from employees order by年薪desc;#按姓名的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, salaryfrom 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 desc, employee_id asc;

总结：orderby子句中可以支持单个字段、多个字段、表达式、函数、别名

order by字句一般放在查询语句的最后面，limit字句除外