How do i convert this to mysqli - php

Question

Im having a problem converting this to mysqli from mysql, i've attempted what the php documentation said but i still can't get it. Any help would be appreciated.
return (mysql_result(mysql_query("SELECT COUNT(id) FROM users WHERE (username = '$username' OR email = '$username') AND password = '$password'"), 0) == 1) ? $user_id : false;
I tried this:
return (mysqli_data_seek(mysqli_query($con,"SELECT COUNT(id) FROM users WHERE (username = '$username' OR email = '$username') AND password = '$password'"), 0) == 1) ? $user_id : false;
Whole function:
function login($username, $password){
$con=mysqli_connect("127.0.0.1","root","","frostbase");
$user_id = user_id_from_username($username);
$username = sanitize($username);
$password = md5($password);
return (mysqli_data_seek(mysqli_query($con,"SELECT COUNT(id) FROM users WHERE (username = '$username' OR email = '$username') AND password = '$password'"), 0) == 1) ? $user_id : false;
mysqli_close($con);
}

Answer 1

You can do it way better actually.
safeMysql is a tool that helps you to convert your ugly old mysql API-based code not to new ugly mysqli API-based code but use way better approach.
The point is that you must not use raw API calls in the application code, be it mysql, mysqli or PDO. But wrap them in a library that will do all the required operations like data binding, fetching, error handling, profiling and many more.
Frankly, you have only to write your query - the rest is done by the lib:
$sql = "SELECT 1 FROM users WHERE (username = ?s OR email = ?s) AND password = ?s";
return (bool)$db->getOne($sql, $username, $username, $password);
or, in a form of a function
function login($username, $password){
global $con; // you have to connect ONCE per application
$sql = "SELECT 1 FROM users WHERE (username = ?s OR email = ?s) AND password = ?s";
return (bool)$con->getOne($sql, $username, $username, $password);
}