访问MySQL数据库中的下一个和上一个记录

Question

Say I have 3 records of same users with IDs 2,4,7,9 and I want to be able to go from one to another by navigation via next/previous links. The problem is, I don't know how to fetch 1 record per page with link redirecting to same page.

So when I have record with ID 4, If I click previous it must redirect me to same page with record of having ID 2 and If I click next it should take me to 7.Please help with redirection and displaying one record per page.

So far I have done:

<?php 
   $query1 = "SELECT * FROM table2 WHERE id='{$user}' order by srno desc " ;
   $result1=mysql_query($query1,$con);
   if (!($result1) )
   {
      die('Error: ' . mysql_error($con));
   }
   else
   {
      $values1= mysql_fetch_array($result1);
   }
    mysql_close($con);
  ?>

Do I need to change query to :

$query1 = "SELECT * FROM table2 WHERE id='{$user}' order by srno desc LIMIT 1 OFFSET 1" ;

Answer 1

I'd use something like this for prev/next links...

html

<a href="?action=prev&id=<?php echo $values['id'] ?>">prev</a>
<a href="?action=next&id=<?php echo $values['id'] ?>">next</a>

php

<?php
    if(!is_numeric($_GET['id'] || $_GET['id'] < 1)
         throw new \Exception('Illegal id value');
    if(!isset($_GET['action']))
         $_GET['action'] = 'view';
    switch($_GET['action']){

        case 'prev':
            $q = "SELECT * FROM table2 WHERE id<'{$_GET['id']}' ORDER BY id DESC LIMIT 1" ;
            break;

        case 'next':
            $q = "SELECT * FROM table2 WHERE id>'{$_GET['id']}' ORDER BY id ASC LIMIT 1" ;
            break;

        case 'view':
            $q = "SELECT * FROM table2 WHERE id='{$_GET['id']}'";
            break;

        default:
            throw new \Exception('Illegal action value');

    }



   $result1=mysql_query($query1,$con);
   if (!($result1) )
   {
      die('Error: ' . mysql_error($con));
   }
   else
   {
      $values1= mysql_fetch_array($result1);
   }
   mysql_close($con);

I didn't understand what srno is, and how did you get your user id in $user var, so I left them out. Code should be functional nontheless, once you understand it, you can use it to rewrite your own.

Answer 2

if you displaying one record per page you may simply use pagination. You can get a pagination example from http://www.tutorialspoint.com/php/mysql_paging_php.htm