Problem with code that checks for duplicate entry of username

Mel

Having trouble getting the section labelled "check for
duplicate entry of username" ... the script works but does not
appear to check for a duplicate username as it accepts further
entries using the same username... has anybody got any ideas
where I am going wrong here

Mel

if ((!$name) || (!$email_adr) || (!$web_adr) || (!$username) || (!$password) || (!$our_link)) {
header("Location: http://localhost/new_register.html");
exit;

}

$db_name = "testDB";
$table_name = "register";

$connection = @mysql_connect("localhost", "sandman", "tQ9472b")
or die("Couldn't connect.");

$db = @mysql_select_db($db_name, $connection)
or die("Couldn't select database.");

//Check for duplicate entry of username

$sql="SELECT * FROM $table_name WHERE username='$username'";
$result = mysql_query($sql) or die("Couldn't execute query.");
$num_rows=mysql_num_rows($result);
if($username>=1):
print "This username is already in use. Please, return and choose another";
exit;
endif;

// End of duplicate check section

// This section inserts form info into table - and is working fine

$sql = "INSERT INTO $table_name
(id, name, email_adr, web_adr, username, password, our_link)
VALUES
(\"\", \"$name\", \"$email_adr\",\"$web_adr\", \"$username\", password(\"$password\"),\"$our_link\")
";

$result = @($sql,$connection) or die("Couldn't execute query.");

Frag

Here is where your error is..

Your checking if $username is >= 1. it should be $num_rows>=1. Below would be a better way to write it..

$num_rows=mysql_num_rows($result);
if($username>=1):
     print "This username is already in use. Please, return and choose another";
     exit;
}

It should be..

if(mysql_num_rows($result)>0) {
     print "This username is already in use. Please, return and choose another";
     exit;
}

Frag