problem with mysql_num_rows()

mwdrago

so, this file was working on my local computer, which runs php 4.3 and apache 2.0, and then I uploaded it to the web server which is apache 1.3 and uses php 4.2.2 and I got this error:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /test/auth.php on line 24

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /test/auth.php on line 48

Warning: Cannot add header information - headers already sent by (output started at /test/auth.php:24) in /test/auth.php on line 49

<?
$db = mysql_connect("localhost", "xxxxxx", "xxxxx") or die("couldn't connect to database");
mysql_select_db("xxxxxxx",$db) or die("couldn't select db");



session_name("");
session_start();

if (!$username || !$password || !$username && !$password)
	{header("location:index.php");}
if ($username && $password)

{
//if the user has just tried to log in


$query = "select * from tblLogin where lgnUserName='$username' and lgnPassword='$password'";
$result = mysql_query($query, $db);




if (mysql_num_rows($result) > 0)
	{
		//if they are in the database register the user id
		$login_array = @mysql_fetch_array($result);

	$session_sessid = $login_array["lgnFanclubNo"];

	$session_valid_user = $username;


	session_register("session_valid_user", "session_sessid");
	$olduser_query = "select * from tblInfo where infFanclubno = '$session_sessid'";
	$olduser = mysql_query($olduser_query);

	if(mysql_num_rows($olduser) > 0) {
	header("Location:member_directory.php");
	}else{


	header("Location:edit_profile.php?fanclubno=$session_sessid");
	}
} elseif (mysql_num_rows($result) == 0)
	{ header("Location:index.php"); }

}






?>

could anyone tell me where I screwed up? I appreciate any help.

reidme

I would guess that the SQL is not working, try putting some error checking in there before the 'if mysql_num_rows($result)' line to check the query is actually being processed.

Kerry_Kobashi

What are the values of username and password before they come into this routine? Aren't these coming in from a form?

Have you checked to see if these are valid POST variables and that they exist?

You should really check for if username or password is empty string or not. I wouldn't use the bang (!) operator on it.

Rather do this:

if ($username != "" || $password != "")

$username and $password's data type are meant to be strings. So test it that way instead of doing !$username and !$password. It will make your code more clearer and others will understand its intent.

Have you checked to see if the results of the first query is valid?

My suggestion is to debug this thing with echo statements checking return values....

mwdrago

thanks for the reply.

I did use die() to see if there was anything going into $result and there wasn't. so I echoed my query and it looked like it should. So the problem isn't with the query....

mwdrago

yes, I have a form with variables $username and $password and the query appears to be ok

reidme

If the $username and $password variables are not set the script should return the browser to index.php, but this isnt happening because of the classic: 'Warning: Cannot add header information - headers already sent by (output started at /test/auth.php:24) in /test/auth.php on line 49' error.
That's why it is continuing through the script and producing the misleading 'Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /test/auth.php on line 24'.

Auth.php is already sending the headers, so you cannot use 'header("location:index.php")' ?
Or has some whitespace sneaked into your script somewhere? Headers must be sent before ANY html code, including a space or newline.

mwdrago

I used ob_start() at the beginning of the script and ob_end_flush(); at the end and it did execute the header info, but the problem is, I put a correct username and password! It shouldn't have sent me back to the index.php page if I put the correct username/password combo.

The variables are set, I've echoed the $query and it looks good, but when it gets to $result, there's nothing going in there.

mwdrago

ok, so I used mysql_error() and it said my table doesn't exist....

I figured it out. The query is case sensitive and when I exported my tables to the online database it changed tblLogin to tbllogin for some reason. So thus the error.