help with some simple PHP codes please

[Darkwoods]

holla... im doing a php news system it is going good so far im tottaly new to PHP so i would need help if anyone could im trying to add data from mysql the data is showing fine but i cant figure out how to make a default $cat to show up im having this code in my index.php and it show up empty if i dont use the $_GET so my question is how can i make a default $cat and if i want to use this code ''ORDER BY id DESC'' how would i do that i tried it with the code below here but it gives me error 

 

please your help would be very nice i have been trying the whole day and i can say i have learned a lot in one day but i wont learn more if i dont ask for help

 

	 $cat = $_GET['cat'];

 	//load contents from the database
	$sql = "SELECT * FROM `contents` where `cat`='$cat'";
	$result = mysql_query($sql, $connect);
	while ($row = mysql_fetch_array($result))
  			{ 

[Bendude14]

first of all add this at the top of the page

 

error_reporting(E_ALL);

 

then to check if $_GET['cat']; is set you can do this

 

<?php
if(isset($_GET['cat'])) { 

//use it
} else { //assign a default value to $cat

?>

 

change this line also

 

      $result = mysql_query($sql, $connect);

 

to

      $result = mysql_query($sql, $connect) or trigger_error("Query Failed" . mysql_error());

 

you can see that we have added some error reporting in case something goes wrong.

 

 

 

[CroNiX]

I usually do:

<?php
$cat = isset($_GET['cat']) ? $_GET['cat'] : "";

 

It looks strange, but it says, if $_GET['cat'] is set, then $cat = $_GET['cat'], if not $cat = ""

if you want $cat to have a default value, then change "" to your default value.

 

As far as your query,

$sql = "SELECT * FROM `contents` where `cat`='$cat' ORDER BY `id` DESC";

should be fine.

 

I would use the error handling as posted by Bendude as well.  It will show you what is wrong, if anything, in your query.

[Darkwoods]

thanks guys it helped alot