PHP Introduction to Learning Knowledge Point 2: PHP Simple Pagination Process and Principles

<?php
require '../inc/';
?>
<?php

//Initial parameter settings
$pagesize=5; //Pagination size
$pagenum=1 ; //Default is the first page


//Step 1: Get which page is currently on
if($_GET){
if($_GET['pagenum']){
$pagenum=$_GET['pagenum'];
}
}
//Step 2: Get the content list of the current page

$sql="Select * From message limit ".($pagenum-1)*$pagesize.",$pagesize ";
$result=mysql_query($sql);

while(($row=mysql_fetch_array($result))==true){
echo '<hr>'.$row["title"].'</hr>';
}

//Step 3: Get the number of records
$sql="Select id From message";
$result=mysql_query($sql);
$rownum=mysql_num_rows($result);

//Step 4: Calculate the number of pages
if(($rownum%$pagesize)==0){
$pagecount=$rownum/$pagesize;
}else{
$pagecount=(int)($rownum/$pagesize);
}

//Step 5: Get the paging link
$url=$_SERVER["REQUEST_URI"];
$url=parse_url($url);
$url=$url["path"];

//Step 6: Output the paging link

if($pagenum==1){
echo "[Page 1] [Previous Page]";
}else{
echo "[<a href=\"$url?pagenum=1\">Page 1</a>] [<a href=\"$url?pagenum=".($pagenum-1)."\">Previous Page</a>]";
}


if($pagecount==$pagenum){
echo "[next page] [last page]";
}else{
echo "[<a href=\"$url?pagenum=".($pagenum+1)."\">Next page</a>] [<a href=\"$url?pagenum=".($pagecount)."\">Last page</a>]";
}

?>