echo a certain number of results per page in php - php

Question

I have a query and loop that displays products depending on an id. Sub-Category id in this case. The code is as follows:
<div id="categoryproducts">
<?php
$productsGet = mssql_query("SELECT * FROM Products WHERE SubCatID = ".$_GET['scid']."");
while ($echoProds = mssql_fetch_array($productsGet)) {
?>
<div class="productbox">
<div class="productboximg">
<img src="<?php echo $echoProds['ProdThumb']; ?>" height="58" width="70" alt="" />
</div>
<div class="productboxdtl">
<h3><?php echo $echoProds['Title']; ?></h3>
<p><?php echo $echoProds['Synopsis']; ?></p>
</div>
<div class="productboxprc">
Price <strong>£<?php echo $echoProds['Price']; ?></strong>
</div>
<div class="productboxmore">
</div>
</div>
<?php
}
?>
<div id="shoplistpagesbot" class="shoplistpages">
Results Pages: 1 2 [Next »]
</div>
I am unsure how to display a certain number of products per page, as shown there is a mechanism for changing between pages, I need to somehow code that after a certain number of products, say 5 for example, the remainder are displayed on the next page.
Can anyone suggest how to do this? Or point me in the correct dirrection as to which functions I should be looking into.
Sorry if it isn't very clear, I am new to PHP. The DB im using is a MS SQL one not MySQL

Answer 1

Depends what version of MSSQL you are using.
I'm not a user of MSSQL, but apparently the SQL Server 2000 uses the TOP command, whilst SQL Server 2005 uses the BETWEEN command. A Google search should provide you with several tutorials on each but I am going to assume that you are using the 2005 version.
To return the items on page number $page_number, the general algorithm is :
// The most common way to specify which page to display is a GET variable. There
// are others ways and if you'd prefer them, just set $page_number to get the
// number from there instead. Don't forget to filter all data from the GET array
// as a user may try to insert harmful data, such as XSS attacks.
$page_number = $_GET['page'];
$scid = $_GET['scid'];
// Calculate the range of items to display.
$min = $page_number * $items_per_page;
$max = $min + $items_per_page;
$sql = "SELECT * FROM Products WHERE SubCatID = \"{$scid}\" BETWEEN {$min} AND {$max}";
To get the remaining number of items, you'll need a separate database query returning the total number of items.
$sql = "SELECT COUNT(*) FROM Products WHERE SubCatID = \"{$scid}\"";
// Using the same $max as before as it is the number of items on the page plus
// total items on previous pages, but we'll redefine it here just in case.
$max = ($page_number * $items_per_page) + $items_per_page;
// Assume that $total_rows is the number returned from executing the count query.
$remaining_items = $total_rows - $max;
Now to generate links to all the other pages.
$current_page = $_GET['page'];
$total_pages = $total_rows / $items_per_page;
if($current_page != 1) {
$previous = $current_page - 1;
echo "Previous";
}
for($i = 1; $i <= $total_pages; $i++) {
echo "{$i}";
}
if($current_page != $total_pages) {
$next = $current_page + 1;
echo "Next";
}

Answer 2

$pagenumber = $_GET['pagenumber'];
$recordsperpage = 30;
$first = ($pagenumber*$recordperpage)-$recordperpage;
$last = $pagenumber*$recordsperpage;
$productsGet = mysql_query("SELECT * FROM Products WHERE SubCatID = '".$_GET['scid']."' LIMIT $first,$last");
Have this at the top of the page and pass a GET parameter in your links e.g. browse.php?pagenumber=1;
You can calculate the number of pages by dividing total rows in the recordset by your $recordsperpage variable.
Then just use a simple for loop to output the navigation links e.g.:
for($i = 1; $i <= $totalpages; $i++) {
echo "<a href='browse.php?pagenumber=$i'>$i</a>";
}
Where $totalpages is the result of dividing total rows in the recordset by your $recordsperpage variable.
Hope this helps
Here it is for MS SQL:
SELECT TOP 10 *
FROM (SELECT TOP 20 * FROM products ORDER BY ID) as T
ORDER BY ID DESC
Basically are selecting the top 10 records from the top 20 in reverse order here. Hence you get the second 10 in the recordset.
Replace the 10 with the number of records per page and the 20 with the $last variable above.
Hope this clears it up