Given your need, you should use express, then the problem becomes:
var express = require('express');
var app = express();
app.get('/', callback_for_root_dir);
app.get('/aboutus', callback_for_aboutus);
app.get('/ourtechnology', callback_for_ourtechnology);
app.get('*', default_callback);
app.listen(80);
Using MySQL for routing would be awkward, because how are you going to define the corresponding callbacks with a new path? You still need to code the callback in Node.js and restart the app, so there is no much point using MySQL data for routing. Besides, you can use powerful regular expressions for paths with Express.