Need some help with an error

code_junkie · 10-13-2009, 02:59 PM

Ok so I've been trying to teach myself php and am doing pretty good so far. I am making a little newsletter sign up for a site and it works fine, but I get an error. From what I understand this error should not allow the script to continue if it happens, but it doesn't and the script runs. The error is:

Code:

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

And like I said the script runs fine, might not be the best way to do it, its a start. Here is what I have done.

Code:

if(isset($_POST['submit'])) {
		//Set variables.
		$firstname = strip_tags($_POST['firstname']);
		$lastname = strip_tags($_POST['lastname']);
		$email = $_POST['emailaddress'];
		$accept = $_POST['accept'];
		
		// Check for empty fields.
		if (empty($firstname) || empty($lastname) || empty($emailaddress)) {
			$message = "Please fill in all fields!";
		} else {
			$message = "All fields have been filled in!";
			// If successful, continue sign up proccess.
			// Check to see if info already exist.
			$sql = "SELECT * FROM mailing_list WHERE firstname = '$firstname' AND lastname = '$lastname' AND email = '$emailaddress'";
			$result = mysql_query($sql) or die(mysql_error());
			if(mysql_num_rows($result) != 0) {
				$message = "This information already exist!";
			} else {
				// If information doesn't exist, add it.
				$sql = "INSERT INTO mailing_list (id, firstname, lastname, email, accept) VALUES (null, '$firstname', '$lastname', '$emailaddress', '$accept')";
				$result = mysql_query($sql) or die(mysql_error());
				if(mysql_num_rows($result) != 0) {
					$message = "Users information was not added!";
				} else {
					$message = "Users information was added successfully!";
				}
			}
		}
	} else {
	}

How can I fix what is triggering this error or stop it from showing?