php分页

##1. 分页原理：

limit offset, size

offset:偏移量  offset=(当前页-1）*size
size:每页显示条数

#2. 排序

order by ‘排序字段’ ‘正序或反序'

3. demo

$doctor=M('freegoods');

       $num=I('page','1','intval');//当前页码

     $pagesize=I('size','5','intval');//每页显示条数

       $count=$doctor->count();//总条数

       $sort=I('sort','id');//当

         $order=I('order','asc');

       $totalpage = ceil($count/$pagesize);//总页数

        $offset = ($num-1)*$pagesize;

   $sql = "select id,doctorname,post,asktime,skill,storecode,gender,userimg from hx_doctor order by $sort $order  limit $offset,$pagesize ";
        $info=$doctor->query($sql);