mysql_num_rows(): supplied argument is not a valid MySQL result resource

mixos

Hi all

This file click.php

<?php

require("phpadmentor_config.php");

if ( $id == -1 )
    $redirurl = $sPhpAdMentor_DefaultClick;
else
    {

//Find the url...

$conn = PhpAdMentor_GetDatabaseConn();

$sSQL = "SELECT
      redirurl
     FROM 
      banner
     WHERE
      bannerid=$id";

$oRS = mysql_db_query( $sPhpAdMentor_DBDatabase, $sSQL, $conn );

if ( mysql_num_rows($oRS) ==0 )

    {
    $redirurl = $sPhpAdMentor_DefaultClick;
    }

else

    {
    $row = mysql_fetch_array($oRS);
    $redirurl = $row["redirurl"];
    //Update stats
    PhpAdMentor_UpdateStats( $conn, $id, true, false );
    }

}

//echo($redirurl);

header("Location: $redirurl");

?>

Produces these errors:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/httpd/vhosts/electronics-lab.com/httpdocs/forum/click.php on line 23

Warning: Cannot modify header information - headers already sent by (output started at /home/httpd/vhosts/electronics-lab.com/httpdocs/forum/click.php:23) in /home/httpd/vhosts/electronics-lab.com/httpdocs/forum/click.php on line 42

and i can't figure out them. Any ideas?

leatherback

Hi,

The warning tells you atht you try to get the number of rows, from an invalid query result. In opther words: THere was an error in you rquery (NOT no results!). You should always place a little line after your query statment, saying something like:

$oRS = mysql_db_query( $sPhpAdMentor_DBDatabase, $sSQL, $conn )or die('The following problem occured when trying to retrieve your data: '.mysql_error());

This will tell you that there was a problem, and stop the script from proceeding.

The rest of the warnings are a result of this: It has given you an error statement, therefor the redirect is not possible anymore.

Fix your query, and your problem is solved.

mixos

Thanks for the answer

If i change this:

$sSQL = "SELECT 
          redirurl 
         FROM  

          banner 
         WHERE 
          bannerid=$id"; 

$oRS = mysql_db_query( $sPhpAdMentor_DBDatabase, $sSQL, $conn );

to this

   $sSQL = "SELECT
	      redirurl
	     FROM 
	      banner
	     WHERE
	      'bannerid'='$id'";

$oRS = mysql_query ($sSQL, $conn) or die ('The following problem occured when trying to retrieve your data: '.mysql_error());

I don't get an error, but it redirects me to the

$sPhpAdMentor_DefaultClick

insted of redirect me to the url fetched from the database.

Any clues?

leatherback

OK,

we are getting somewhere.

THen the $ID is not passed to the script (The error stopped, so now the query is uinderstood. But there is no value in $id, which means there was no URL selected).

I suppose you get ID through a link or a form.

If it is a link, place this line:

$id = $_GET[id];

at the top of the page

if it was a form, place:

$id = $_POST[id];

at the top of the page.

That should solve it.

mixos

The id is in a URL like this one:

.... /click.php?mgr=aspcode.net&id=37

I placed:

$id = $_GET[id];

just under

and i take the same results as previous.

mixos

It seems to get the id now, because if I add:

$id = $_GET[id];
echo "$id";

this come up:

37
Warning: Cannot modify header information - headers already sent by (output started at /home/httpd/vhosts/electronics-lab.com/httpdocs/advertising/click.php:4) in /home/httpd/vhosts/electronics-lab.com/httpdocs/advertising/click.php on line 48

where 37 is the specified id

mixos

No solution yet. This must be a more generous problem as this script stopped working on it's own.... mabe due to a server upgade. No problem with the db... maybe a problem with the url that calling the url?

leatherback

Oh,

sorry. I figured from my earlier post you would have figured oput you need to leave out the echo $id line.

Remove that, and the errors should disappear, and the script should work/

mixos

I am sorry to tell you that this didn't solve the problem. It's still excecutes:

$redirurl = $sPhpAdMentor_DefaultClick;

laserlight

Post your updated code.

mixos

With this code

<?

$id = $_GET[id]; 

require("phpadmentor_config.php");

if ( $id == -1 )
    $redirurl = $sPhpAdMentor_DefaultClick;
else
    {
    //Find the url...

$conn = PhpAdMentor_GetDatabaseConn();
$sSQL = 'SELECT 
      redirurl 
     FROM  
      banner 
     WHERE 
      bannerid= $id'; 

$oRS = mysql_query ($sSQL, $conn) or die (mysql_error());


if ( mysql_num_rows($oRS) == 0 )
    {
    $redirurl = $sPhpAdMentor_DefaultClick;
    }
else
    {
    $row = mysql_fetch_array($oRS);
    $redirurl = $row["redirurl"];
    //Update stats
    PhpAdMentor_UpdateStats( $conn, $id, true, false );
    }
}
//echo($redirurl);
header("Location: $redirurl");
?>

I get:

Unknown column '$id' in 'where clause'

leatherback

Well,

You changed the double quotes around your query to single quotes, and removed the single quotes. Why?

The query should be as in your first post, or:

$sSQL = "SELECT
      redirurl
     FROM 
      banner
     WHERE
      bannerid='$id' ";

mixos

Ok, the updated code is:


$sSQL = "SELECT 
      redirurl 
     FROM  
      banner 
     WHERE
      bannerid = '$id'"; 

$oRS = mysql_query ($sSQL, $conn) or die (mysql_error());

and guess.... It's working !! 🙂

Thanks for your great help !! I wish the best.

mixos

I concluded that the problem caused by

register_globals setting in php.ini

That's because the admin panel of the same script didn't work either. So the problem was generous and not only in click.php.

Now click.php is optimized to work with register_globals=off but doesn't happen the same with the rest code of this script.

Then i turnned register_globals=on and everything is working nice.

In case someone is interested optimize the rest of the code to work with register_globals=off I attach the whole script here.

leatherback

Hi Mixos,

Well, yes. That was clear from the point where you said that $id was not set, and that the script stopped working (You should actually mention that next time, it helps enourmously when debugging).

Anyway. You would be better of settgiong the register_globals to off again. It is a security hazard, since people can actually set your variables for you, and that way inject scripts in your page.

Recode your pages accordingly.

mixos

What's the difference between register_globals off and on?

This is not a script that i wrote so i can't rewrite it.... i can only undestund the basics, so any hints on this will be really helpfull (how to make it register_globals=off compatible)

laserlight

It has to do with incoming variables.
Actually, if you had stated that say, $sPhpAdMentor_DefaultClick was an incoming variable, the problem would have been detected and solved very quickly.

PHP Manual -> Using Register Globals

leatherback

Hi Laser,

Actually the $id was the incoming one, but yes. It would have been solved very quickly. And as mentioned bfore.. Stating that the script stopped working after a server upgrade would have helped a lot..

Mixos: To make it work in a register_globals off env. you need to get each variable which is passed to the script (Either via a link or via a form) specifically included in your page.

For form variables:

$variable = $_POST['variable'];

For URL transmitted variables:

$variable = $_GET['variable'];

Even better is to check whether these variables are like you expect them to be, and run html_special_chars() over them before using them, unless you know there are HTML based characters in it.