[Audaxviator]

isRegistered(bla-bla);

async function isRegistered(id) {
  var sel_query = await new Promise( resolve => {
    con.query('SELECT * FROM `users` WHERE `userid`= ?', id, function(error, results) {
      if(err) console.error(err);
      resolve(results);
    });
  }).then( result => {
    return result;
  };
  if(sel_query.length != 0) {
    console.log(1, sel_query);
  } else {
    console.log(0);
  }
}