Problem with mysql_num_rows

owainhunt

Whenever I try to use the mysql_num_rows() function (eg to check username/password combinations or multiple usernames) I get the error 'Supplied argument is not a valid resource'.
Anyone know what I may be doing wrong?

Anon

There may be quite a few reasons for this error.

It may be because there is some syntax error in ur query or u may not be passing the correct result set parameter to mysql_num_rows(int result).
Hope this helps u, if not let me know what code u actually used so that I can tell u where u went wrong.

kennethl

"Supplied argument is not a valid resource" sounds like there was some error in the execution of your query. See if "echo mysql_error();" gives any more info about what's going wrong.

owainhunt

Here's the code
require('config.php');
$db = mysql_connect($host, $user);
mysql_select_db("members",$db);
$sql="SELECT * FROM details WHERE (username=$username)";
$result = mysql_query($sql);
$check_num = mysql_num_rows($result);
$sql_insert="INSERT INTO details (first, last, username, password, email, location, URL, title) VALUES ('$first','$last','$username','$password','$email','$location','$URL','$title')";

if ($check_num > 0){
?>
Sorry, that username has already been taken. Please hit you back button and choose another.
<?php
}else{
mysql_query($sql_insert);
}

And here's the error I get
Warning: Supplied argument is not a valid MySQL result resource in d:\adduser.php on line 7
Line 7 is $check_num = mysql_num_rows($result);

kennethl

Looks like you need some single quotes around $username in your query. Try:

SELECT * FROM details WHERE username='$username'

owainhunt

Hot-diggity-damn! Always the simple things isn't it!?
Cheers.