how to get last id in database

// Insert query 
$query = "insert into users(username,fname,lname) values('sonarika','Sonarika','Bhadoria')"; 

mysqli_query($con,$query); 

// Get last insert id 
$lastid = mysqli_insert_id($con); 

  $db = db_connect();
  $query = $db->query("SELECT * FROM users ORDER BY id DESC LIMIT 1");
  $result = $query->getRow();