Detailed explanation of how to create simple paging (read records from database) using php

$conn = mysql_connect('localhost','root','');
            mysql_select_db('db_BookStore',$conn);
            mysql_query("set names utf8");
if(isset($_GET['page']))                                                                                                                       �
            {
                $page = intval($_GET['page']);
            }
            else
            {
                $page = 1;
            }
$page_size = 2; //Maximum number of records
            $sql = "SELECT count(*) as amount FROM tb_BookInfo";
            $result = mysql_query($sql);
            $row = mysql_fetch_array($result);
//Calculate the total number of pages
            $amount = $row['amount'];
            if($amount)
            {
                if($amount < $page_size){$page_count = 1;}
                if($amount % $page_size){$page_count = (int)($amount / $page_size) + 1; }
                else{$page_count = $amount / $page_size;}
            }
            else
            {
                $page_count = 0;
            }
//Page turn link
            $page_string = "";
            if($page == 1)
            {
$page_string .= "Home | Previous Page";
            }
            else
            {
$page_string .= "<a href='?page=1'>Home</a> | <a href='?page=".($page-1)."'>Previous Page</a>";
            }
            $page_string .= "| $page |";
            if($page == $page_count)
            {
$page_string .= "Next Page | Last Page";
            }
            else
            {
$page_string .= "<a href='?page=".($page+1)."'>Next Page</a> | <a href='?page=$page_count'>Last Page</a>";
            }
        $sql = "select * from table order by id desc limit ". ($page-1)*$page_size .", $page_size";
　        　$result = mysql_query($sql);
while ( $row = mysql_fetch_row($result) ){
　$rowset[] = $row;
　}
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