排序(默认：asc升序; desc降序
如：根据成绩从高到低排序
select * from stu_info order by mark desc;
根据成绩从低到高排序
select * from stu_info order by mark asc;
mysql中排序
原文：http://www.cnblogs.com/xiaomingzaixian/p/7309016.html
