Link til forrige og næste id

Kode 

<?php print projectLinksNextPrev($_GET['project_id']); ?>

PHP kode 

 <?php
     
     
     function projectLinksNextPrev($project_id) {
      //Connect to db
      $link = mysql_connect("","","");
      mysql_select_db("", $link);
      
      //Create variables for previous and next links
      $prev_id = $id - 1;
      $next_id = $id + 1;
      
      //call db to find out if previous project_id exists
      $result = mysql_query("SELECT * FROM `cases` WHERE `id`=$prev_id", $link);
      $num_rows_prev = mysql_num_rows($result);
      //call db to find out if next project_id exists
      $result = mysql_query("SELECT * FROM `cases` WHERE `id`=$next_id", $link);
      $num_rows_next = mysql_num_rows($result);
      $output = '';
      if($num_rows_prev != 0) {
          $output .= '<li class="prev"><a href="./?id='.$prev_id.'"><img src="../../img/main/32px/arrow-left2.png" width="32" height="32" alt="Forrige">Forrige</a></li>';
      }
      if($num_rows_next != 0) {
          $output .= '<li class="icon-case"><a href="../"><img src="../../img/main/32px/stack.png" width="32" height="32" alt="Oversigt"></a></li>
          <li class="next"><a href="./?id='.$next_id.'">Næste<img src="../../img/main/32px/arrow-right2.png" width="32" height="32" alt="Næste"></a></li>';
      }
      return $output;
  }
     
     
     ?>
     <?php print projectLinksNextPrev($_GET['project_id']); ?>

Kode 

function projectLinksNextPrev($project_id)

Kode 

$prev_id = $id - 1;
$next_id = $id + 1;

Kode 

$prev_id = $project_id - 1;
$next_id = $project_id + 1;

Problemet er ikke så stort. Det er sjovt at du ikke får en fejl. Kig i koden.

Kode 

function projectLinksNextPrev($project_id)

Og herefter kigger du i linje 10 og 11 så står der

Kode 

$prev_id = $id - 1;
$next_id = $id + 1;

Burde det ikke være mere korrekt hvis du havde skrevet

Kode 

$prev_id = $project_id - 1;
$next_id = $project_id + 1;

Kode 

function projectLinksNextPrev($project_id)

Kode 

function projectLinksNextPrev($id)

Hvorfor er der ingen der vil bruge Union? :o)

SQL kode 

 SELECT [IdField], 'Prev' AS pos FROM [MyTable] WHERE [IdField] < [CurrentId] ORDER BY ID DESC LIMIT 1
 UNION
 SELECT [IdField], 'Next' AS pos FROM [MyTable] WHERE [IdField] > [CurrentId] ORDER BY ID ASC LIMIT 1

Så slipper man også for et SQL kald.

PHP kode 

 // Kun for illustration:
 $rows = $db->fetchAll($sql);
 // The loop
 foreach($rows as $row) {
     if($row['pos'] == 'Prev') {
         // ....
     } elseif($row['pos'] == 'Next') {
         // ....
     }
 }