Variable help

[Sharif]

In my code, if the variable: ID is given in the url as a NUMBER, it works, but if it's given as a word (for testing perposes) it gives me an error:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /news.php on line 163

Here is the code use by the way:

<?php
if (isset($id) && is_numeric($id)) //If there is an ID given, and it's a number:
{
         echo ''; // it will display nothing
}
else
{
	$query = "SELECT id FROM news WHERE id=$id";
	$result = mysql_query($query);
	if(mysql_num_rows($result) > 0) // If the ID given exists
	{ // It outputs the following:
	echo '<table width="630" border="0" align="center" cellpadding="0" cellspacing="0" class="bodyTEXT">
				<tr valign="middle"> 
					<td align="center">
					<a href="http://forums.onlyonxbox.net">
					<img src="http://forums.onlyonxbox.net/templates/subSilver/images/folder.gif" alt="Discuss In The Forums" border="0"></a>
					&nbsp;
					<a href="http://forums.onlyonxbox.net" class="bodynav">Discuss In The Forums</a>
					&nbsp;&nbsp;|&nbsp; 
					<a href="printnews.php"><img src="images/mini/print.jpg" alt="Printable Version" border="0"></a> 
					<a href="printnews.php" class="bodynav">Printer Friendly Version</a>
					&nbsp;&nbsp;|&nbsp; 
					<a href="send.php"><img src="images/mini/email.gif" alt="Send To A Friend" border="0"></a> 
				     <a href="send.php" class="bodynav">Send To A Friend</a>
					</td>
				</tr>
		</table>';
      }
}
?>

[DigitalExpl0it]

have you tried somthing liek this for your sql statement?

<?
//Connection here
$connect = mysql_connect($hip, $duser, $dpass) or die ("<b><center>".mysql_errno().": ".mysql_error()."</b></center>\n");
$db = mysql_select_db($dname, $connect) or die ("<b><center>".mysql_errno().": ".mysql_error()."</b></center>\n");

//Statement here
$query = "SELECT id FROM news WHERE id='".$_REQUEST["id"]."'";
$results = mysql_query($query, $connect); 
?>

[Sharif]

I dont think it's the statement that is affecting what I want it to do...

[Sharif]

I think I figured it out, why not change:

if (isset($id) && is_numeric($id))

Which, if I understand correctly, in Human, says If the ID is there and it's a number...

to

if (empty($id) || !is_numeric($id))

Which, by my mind, in Human, says If the ID is not there OR it isn't a number...

Am I right?

[tomhath]

Almost. These two are equivalent:

if ( ! (isset($id) && is_numeric($id) ) )

if ( (!isset($id))  || (!is_numeric($id) ) )

There is a difference between !isset() and empty() however.

If a variable is not set, it doesn't exist (there is no variable with that name).

If there is a variable with that name, but it has a zero or null value, then it's empty.

[Sharif]

Okay so let me see if I understand what each means...

if ( ! (isset($id) && is_numeric($id) ) ) // If there is no ID and it isn't a number

if ( (!isset($id))  || (!is_numeric($id) ) ) // If there isn't a number or it's not a number

I think the "!" means that if it isn't there or if it's false right? I think I'm going to go with the second one, because that says if there isn't a variable given or it isn't a number it will display the error I want...

[tomhath]

I think of the first slightly differently:

        if (    !                          (isset($id) && is_numeric($id)     )   ) 
// If   not    (there is an id and it is a number)