node-mysql query issue

node-mysql

var sys = require('sys');
var io = require('socket.io');
var http = require('http');
var db_client = require("mysql").Client;
var db = new db_client();
db.user = "root";
db.password = "hello"
db.connect();
db.query("USE development_test");

server = http.createServer(function(req, res) {
    // your normal server code
//    res.writeHead(200, {'Content-Type': 'text/html'});
//    res.end('<h1>Hello world</h1>');
});

server.listen(8080);

var socket = io.listen(server);

var clients = [];

Array.prototype.each = function(fn) {
	for(i=0;i< this.length;i++)
		fn(i,this[i])
}

socket.on('connection', function(client){
	// new client is here!
	client.on('message', function(msg) {
		if(client.user_id == null) {
			client.user_id = msg.user_id
			// now we need to subscribe u to people u r both way frnds with
			r = db.query("select user_id from friends where user_id IN (select to_id from friends where user_id = " + client.user_id + ") and to_id = " + client.user_id, function(err, results) {
				if (err) {
					throw err;
				}
				console.log(results);
			});
			clients.push(client);
		}
		else if(msg.text != null) {
			//we are chatting now...
			client.broadcast({
				text: msg.text
			});
		}
	});
	client.on('disconnect', function() {
		clients.each(function(index){
			if(clients[index].sessionId == client.sessionId)
				clients.splice(index,1);
		});
	});
});
db.end();