node.js mysql query回调函数中再次执行query失败

[wormtown]

var mysql      = require('mysql');
var connection = mysql.createConnection({
    host     : 'localhost',
    user     : 'root',
    password : 'root',
    database : 'poms'
});
connection.connect();

connection.query("select count(*) as count from pom_message_source", function(err, countResult){
    var count = countResult[0].count;
    console.log(count);
    connection.query("select * from pom_message_source where source_id=1", function(err, results){
        if(err){
            console.log("查询错误");
        }
        console.log(results);
    });
});

for(var i=0; i<1; i++){
    connection.query("select * from pom_message_source where source_id=?",i+1, function(err, results){
        if(err){
            console.log("查询错误");
        }
        console.log(results);
    });
}

connection.end();

控制台输出：
1
查询错误
undefined
[ RowDataPacket {
source_id: 1,
source_name: '安迅思 ICIS',
domain: 'http://e.icis-china.com/',
my_encoding: 'utf-8',
seed_urls: '\'http://e.icis-china.com/news?page=1\', \'http://e.icis-china.com/news?page=2\', \'http://e.icis-china.com/news?page=3\'',
seed_url_format: '$(\'.com-list>ul>li>div[class=\\"text\\"]>a\')',
key_words_format: 'null',
title_format: '$(\'title\').text()',
date_format: '$(\'span[class=\\"date\\"]\').eq(0).text()',
author_format: '$(\'.editor>p\').eq(0).text()',
content_format: '$(\'.editor\').text()',
weight_value: 1.5 } ]

请问query的回调函数中是否可以再次执行query查询