<?php

// FILENAME: SHOW-THREAD.PHP

// include_once( "../config.inc.php" );
// the max number of posts per thread was set in the config file perhaps
// e.g. $config['max_posts_per_thread'] = 10;

// A single thread ID may have multiple pages, we check to see if the multipage
// ID (p) is set. e.g. http://www.example.com/forum/show-thread.php?t=123&p=2
$page   = 1;
if( isset($_REQUEST['p']) )
    $page = intval( $_REQUEST['p'] ); // 2
if( $page<1 )
    trigger_error( "Invalid Page ID.  Halting Script...", E_USER_ERROR );
// page 1 starts at offset 0; page 2 starts at offset 10, page 3 starts at offset 20, etc.
$offset = $page * $config['max_posts_per_thread'] - $config['max_posts_per_thread'];  

// screen the thread ID i.e. "t=123"
$thread = 0;
if( isset($_REQUEST['t']) )
    $thread = intval( $_REQUEST['t'] ); // 123
if( !$thread )
    trigger_error( "Invalid Thread ID.  Halting Script...", E_USER_ERROR );

// get the posts
$sql   =  "SELECT SQL_CALC_FOUND_ROWS
          `threads`.`title` AS `thread_title`,
          `posts`.`title`, `posts`.`message`, `posts`.`userid`, `posts`.`post_timestamp`
          FROM `posts`
          LEFT JOIN `threads`
            ON `posts`.`thread_id` = `threads`.`id`
          WHERE `posts`.`thread_id`=$thread
          ORDER BY `posts`.`thread_id`, `posts`.`post_timestamp`
          LIMIT $offset, {$config['max_posts_per_thread']}";
$result = mysql_query( $sql, $conn );
while( $row=mysql_fetch_assoc($result) )
{
    // process the posts to be displayed.    
}
            
// to link to the other multipages off this thread, you need the TOTAL number of posts.
$sql         = "SELECT FOUND_ROWS()";
$result      = mysql_unbuffered_query( $sql, $conn );
$row         = mysql_fetch_row( $result );
$total_posts = $row[0]; // if there are 1002 posts in thread ID 123, $total_posts will now be set at 1002.

// do the necessary math to display the multipage links.
$total_pages    = ceil( $total_posts / $config['max_posts_per_thread'] ); // ceil( 1002/10 ) == 101 pages of 10 posts each
?>

$sql = "SELECT SQL_CALC_FOUND_ROWS * FROM forum_thread LEFT JOIN forum_assoc ON forum_thread.assoc_forum_id = forum_assoc.id WHERE forum_thread.assoc_forum_id = '$forum' LIMIT '$offset', {$config['max_threads_per_forum']}"; 

<?php

// see example code from previous post above...

// do the necessary math to display the multipage links.
$total_pages    = ceil( $total_posts / $config['max_posts_per_thread'] ); // ceil( 1002/10 ) == 101 pages of 10 posts each

// dislay the multipage links...
$mp_links = "<div class=\"mplinks\">";
for( $i=1; $i<=$total_pages; $i++ )
{
  if( $page != $i )
  {
    if( $i != 1 )
    {
       $mp_links .= "<a href=\"$_SERVER[PHP_SELF]?t=$thread&amp;p=$i\">$i</a> | ";
    }
    else
    { // we drop the "&amp;p=1" since the first page is always "/show-thread.php?t=nnn" only.
       $mp_links .= "<a href=\"$_SERVER[PHP_SELF]?t=$thread\">$i</a> | ";
    }
  }
  else
  { // don't need a link here, since we're already viewing this page.
    $mp_links .= "$i | ";
  }
}
// remove the trailing " | " and close the div.
$mp_links = rtrim( $mp_links, " |" ) . "</div>";

// etc...
?>

$sql = "SELECT
        SQL_CALC_FOUND_ROWS
        *
        FROM `forum_thread`
        LIMIT 0, 3";