升序是asc ，降序是desc
按照name排序：
select * from user where age>18 order by name
order by 排序默认是升序排序
上述的SQL语句等同于 select * from user where age >18 order by name asc
select * from user where address=‘河北‘ order by age asc
| id | name | address | age |
| 1 | zhangsan | 河北 | 19 |
| 3 | zhaofeng | 河北 | 20 |
| 4 | liangru | 河北 | 21 |
原文：http://www.cnblogs.com/xuesheng/p/7712240.html