Selecting records in a MySQL database where id != 0 - php

Question

I'm having trouble with my site.
I have a photographs table with id's. THis table is populated when a user uploads a file to the server, which is fine. I also have a forum where images can be posted, and the images are sent to the same photograph table. On the homepage there is a section where one of the photographs from this table shows up with Pagination links below it.
Now when someone posts to the forum and they do not include an image it breaks. That thread won't show up because it's looking for the photo_id of 0, which didn't exist. So I uploaded a dummy image, changed the id value to zero and tried
$sql = "SELECT * FROM photographs HAVING id != 0 ";
$sql .= "LIMIT {$per_page} ";
$sql .= "OFFSET {$pagination->offset()}";
Which worked, the image no longer shows up, but the pagination still thinks that there is a record there. It shows a link for that image and when a user clicks on it it breaks and removes a bunch of other links and it's a mess.
Is it possible to Select everything from the database but not the 0 record, or maybe remove the link from the pagination links? Here is the code:
//1. the current page number ($current_page)
$page = !empty($_GET['page']) ? (int)$_GET['page'] : 1;
//2. records per page ($per_page)
$per_page = 1;
//3. total record count ($total_count)
$total_count = Photograph::count_all();
//Find all photos
//use Pagination instead
//$photos= Photograph::find_all();
$pagination = new Pagination($page, $per_page, $total_count);
//Instead of finding all records, just find the records
//for this page
$sql = "SELECT * FROM photographs HAVING id != 0 ";
$sql .= "LIMIT {$per_page} ";
$sql .= "OFFSET {$pagination->offset()}";
$photos = Photograph::find_by_sql($sql);
//Need to add ?page=$page to all links we want to
//maintain the current page(or store $page in $session)
?>
<div id="right">
<?php
foreach($photos as $photo):
?>
<h3 style="margin: 0;"></h3>
<div style="padding: 5px;">
<img src="<?php echo $photo->image_path(); ?>" width="200" alt="Photo Share Photo" />
<p align="center"><?php echo $photo->caption; ?></p>
</div>
<?php }
endforeach;
?>
<div id="pagination" style="clear: both;" align="center">
<?php
if($pagination->total_pages() > 1) {
if($pagination->has_previous_page()) {
echo "<a href=\"index.php?page=";
echo $pagination->previous_page();
echo "\">« Previous</a> ";
}
for($i=1; $i <= $pagination->total_pages(); $i++) {
if($i == $page) {
echo " <span class=\"selected\">{$i}</span> ";
} else {
echo " {$i} ";
}
}
if($pagination->has_next_page()) {
echo " <a href=\"index.php?page=";
echo $pagination->next_page();
echo "\">Next »</a> ";
}
}
?><br />
<div align="center">
Upload a new photograph
</div>
[EDIT]
Pagination code.
class Pagination {
public $current_page;
public $per_page;
public $total_count;
public function __construct($page=1, $per_page=20, $total_count=0){
$this->current_page = (int)$page;
$this->per_page = (int)$per_page;
$this->total_count = (int)$total_count;
}
public function offset() {
//Assuming 20 items per page:
//page 1 has an offset of 0 (1-1) * 20
// page 2 has an offset of 20 (2-1) * 20
//in other words, page 2 starts with item 21
return ($this->current_page - 1) * $this->per_page;
}
public function total_pages() {
return ceil($this->total_count/$this->per_page);
}
public function previous_page() {
return $this->current_page - 1;
}
public function next_page() {
return $this->current_page +1;
}
public function has_previous_page() {
return $this->previous_page() >= 1 ? true : false;
}
public function has_next_page() {
return $this->next_page() <= $this->total_pages() ? true : false;
}
}
I will look into the total_pages and get back to you if it works. I think I can just add WHERE id != 0 to the end of the count_all method. I don't think anything else uses it other than the photo share. I'll have to look into the code.
Thanks for your help with this.
DC
I simply added:
public static function count_all() {
global $database;
$sql = "SELECT COUNT(*) FROM ".self::$table_name." WHERE `id` **!= 0 AND `show` != 0";**
$result_set = $database->query($sql);
$row = $database->fetch_array($result_set);
return array_shift($row);
}
I added this to the photograph object. Now users can select whether or not that want their image to show in the photo sharing section, and if they don't upload an image with their post then it is automatically assigned the ID of 0. If this isn't clear and someone needs help with it, let me know.

Answer 1

As G-Nugget mentioned. NULL is better suited for this.
Your query also looks odd. The usual syntax is:
SELECT * FROM photographs WHERE id != 0
Having is used to apply filtering on GROUP BY queries.
Edit:
It also looks like you are using $total_count from pagination here:
$total_count = Photograph::count_all();
<snip>
for($i=1; $i <= $pagination->total_pages(); $i++) {
if($i == $page) {
echo " <span class=\"selected\">{$i}</span> ";
} else {
echo " {$i} ";
}
This will show a link for more pages than exist since $total_count includes the 0 record.