int PAGE_NUM=10;// 一页显示10条记录
int pageNum =1;//当前在第几页
int offset= PAGE_NUM * pageNum - PAGE_NUM;
offset=offset<=0?0:offset;
int limit=PAGE_NUM;//显示的条数
select * from tablename order by id limit offset,limit
select * from tablename order by id limit 0,10 --显示1-10, 10条记录
select * from tablename order by id limit 5,10 --显示6-15, 10条记录