db.js 代码：

console.log("开始连接mysql......");
var conn = require("mysql").createClient({
    'host':'localhost',
    'port':'3306',
    'user':'root',
    'password':''
});

ClientConnectionReady = function(client){
client.query('USE nodejs',function(error,results){
    if(error){
        console.log("数据库连接错误:" + error.message);
        client.end();
        return;
    }
    console.log("已经建立到数据库:nodejs的连接");

    //插入一条测试数据
    var sql = "INSERT INTO test SET id=?, user_name=?, nick_name=?",
        values = [ , "jim", "jimmy"];
    client.query(sql, values, function(error, results){
        if(error) {
            console.log("插入记录出错: " + error.message);
            client.end();
            return;
        }
        console.log('Inserted: ' + results.affectedRows + ' row.');
        console.log('Id inserted: ' + results.insertId);
    });

    getData(client);
});
}

getData = function(client){
var sql = "select * from test";
client.query(sql, function selectCb(error, results, fields){
    if(error){
        console.log('查询出错:'+error.message);
        client.end();
        return;
    }
    console.log("查询表:test");
    //console.log(fields);
    console.log('查到结果:' + results.length + "条");
    if(results.length > 0){ //查看第一条记录
        var firstResult=results[0];
        console.log('id:' + firstResult['id']);
        console.log('user_name:' + firstResult['user_name']);
        console.log('nick_name:' + firstResult['nick_name']);

    }
});
client.end();
console.log("关闭数据库连接");
}

ClientConnectionReady(conn);