PHP mysql bug query - php

Question

Hi guys i've been working for straight 12 hours, i can't seem to find fix.
i'm trying to compare user-input to database result for example $username == $result echo "Username is aldready taken, but the problem is it's passing through 2 statements without a break, and if i put a break to exit the loop, it always check for $email == $result2 despite of not entering any email in the field.
if (isset($_POST['username']) or isset($_POST['email'])) {
$extract = mysql_query("
SELECT
`username`, `email`
FROM `users`
WHERE `username`='$username' OR `email`='$email'
");
$resultq = mysql_num_rows($extract);
while ($row = mysql_fetch_array($extract)) {
$result = $row['username'];
$result2 = $row['email'];
echo " " . $result;
echo " " . $result2;
if ($username == $result) {
echo " Username is already Taken!";
// break; //whenever i put break, it always gives me the else if statement echo, despite not entering any email in the field
} //$pass = $_POST['pass'];
else if ($email == $result2) {
echo "Email Address is already used!";
// break;
} else {
}
}
}

Answer 1

Upgrade from mysql to either MySQLi, or PDO.
However;
$extract= mysql_query("SELECT username, email FROM users where username='$username' or email='$email'");
$resultq = mysql_num_rows($extract);
if($resultq > 0) {
echo 'Either your username, or email is already taken!';
return;
}

Answer 2

See sniko for the answer to your initial problem. However, see the following...
You're not defining $username or $email
if ($username == $result ) should be
if ($_POST['username'] == $result )
or you could define $username and $email at the beginning of the conditional.
You should also change this:
isset($_POST['username']) or isset($_POST['email'])
to this:
isset($_POST['username']) && isset($_POST['email'])
because you depend on both in your query.
and as sniko said, switch to mysqli or PDO. mysql_ is deprecated.
full sample:
if(isset($_POST['username']) && isset($_POST['email']))
{
$username = $_POST['username'];
$email = $_POST['email'];
$extract= mysql_query("SELECT username, email FROM users where username='$username' or email='$email'");
$resultq = mysql_num_rows($extract);
if($resultq > 0) {
echo 'Either your username, or email is already taken!';
return;
}
}
Also note, you're not sanitizing the input. You could be hacked with this input. switching to mysqli or pdo and using prepared statements would help this.