Sorting a query via link...

[Advari]

Im making a site, and I want it to sort the results when you click what you want it to sort by... Im relatively new to PHP (1 or 2 days) so i cant really say what im doing wrong or right... So here is the code i currently have. Corrections, or even ideas for a better way to do this would be appreciated. Also of note, I intend to have a paging (next prev) type of thing later.

global $sorttype, $sortval;
$sorttype = 'Brand';
$sortval ='DESC';
$sortval = urldecode($sortval);
$sorttype = urldecode($sorttype);
$query = "SELECT FROM Amalgamators ORDER BY Amalgamators.$sorttype $sortval";
//$result = mysql_query("SELECT FROM Amalgamators ORDER BY Amalgamators.$sorttype $sortval",$dbh);
$result = mysql_query($query);

echo "<p>$sorttype</p><p>$sortval</p>\n";

echo "<table border=1>\n";

echo "<td>Brand</td> <td>Name</td> <td><a href=$PHP_SELF?sorttype=Price&&sortval=DESC>Price</a></td> <td>Picture</td> </tr>\n";

while ($myrow = mysql_fetch_row($result)) {

{{{Tables stuff here}}}

[xblue]

Hi,

you are setting the variables to 'Brand' and 'DESC' no matter of what is passed via url (btw, variables are not persistent between calls, if that is why you defined them as globals).

Instead of
global $sorttype, $sortval;
$sorttype = 'Brand';
$sortval ='DESC';

you'd need to use (assuming register globals are turned off):
$sorttype = $GET['sorttype'];
$sortval =$GET['sortval'];

to improve this further, you could check for allowed values (valid column names) and else use a default to avoid mysql errors, e.g.:

switch ($GET['sorttype']){
case 'Brand':
case 'Price':
    $sorttype = $_GET['sorttype'];
    break;
default:
    $sorttype = 'Brand';

}