PHP pagination function displays data

Recently, Mo Fangshu's website created a page with all comments and directly called some fields in the wp database. This is not difficult. For me, a newbie who just learned PHP, the most difficult thing is the paging function. At the beginning, I used the most Basic paging code is implemented, but the code and experience are very poor. It only realizes page turning up and down. Later I found this function, which is not bad. I would like to share it:
Create a mypage.php file and load it later.

if(!function_exists("pageDivide")){
#$total total information
#$shownu display quantity, default 20
#$url link to this page
function pageDivide($total,$ shownu=20,$url=''){
#$page current page number
#$sqlfirst mysql database starting item
#$pagecon paging navigation content
global $page,$sqlfirst,$pagecon,$_SERVER;
$GLOBALS ["shownu"]=$shownu;

if(isset($_GET['page'])){
$page=$_GET['page'];
}else $page=1;

#if$ The url uses the default value, which is a null value, and the value is assigned to the URL of this page
if(!$url){ $url=$_SERVER["REQUEST_URI"];}

#URL analysis
$parse_url=parse_url($url);
 @$url_query=$parse_url["query"]; //Get the content after the question mark?
if($url_query){
$url_query=preg_replace("/(&?)(page=$page)/","" ,$url_query);
$url = str_replace($parse_url["query"],$url_query,$url);
if($url_query){
$url .= "&page";
}else $url .= " page";
}else $url .= "?page";

#Page number calculation
$lastpg=ceil($total/$shownu); //Last page, total number of pages
$page=min($lastpg, $page);
$prepg=$page-1; //Previous page
$nextpg=($page==$lastpg ? 0 : $page+1); //Next page
$sqlfirst=($page -1)*$shownu;

#Start paging navigation content
$pagecon = "Show first".($total?($sqlfirst+1):0)."-".min($sqlfirst+$shownu,$total )." records, a total of $total records";
if($lastpg<=1) return false; //If there is only one page, jump out

if($page!=1 ) $pagecon .=" Homepage "; else $pagecon .="Homepage";
if($prepg) $pagecon .=" Previous page "; else $pagecon .=" Previous page";
if($nextpg) $pagecon .=" Next page "; else $pagecon .=" Next page";
if($page!=$lastpg) $pagecon.=" Last page "; else $pagecon .=" Last page";

# Drop down jump list, loop through all page numbers
$pagecon .="Go to n";
for($i=1;$i<=$lastpg;$i++){if( $i==$page) $pagecon .="$in";
else $pagecon .=" $in";
}
$pagecon .=" page, total $lastpg page";
}
}else die('pageDivide() function with the same name already exists!');
 ?>

require_once('mypage.php');
$result=mysql_query("select * from table", $myconn);
$total=mysql_num_rows($result); //Get the total number of information
pageDivide($total,10); //Call the paging function, parameter two is the number of items displayed on each page

//Database operation, select the data of your own database, this is just an example, the database link is closed, there is no operation here Explained.
$result=mysql_query("select * from table limit $sqlfirst,$shownu", $myconn);
while($row=mysql_fetch_array($result)){
//Data operation
}
echo $pagecon; // Output paginated navigation content
?>