node.js MySQL不能红色属性为＆＃39; 0＆＃39;未定义

Question

我的路由器中有这个代码：

var express = require('express');
var router = express.Router();
var mysql = require('mysql');

var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'nodejs',
  password : '',
  database : 'nodejs'
});
router.get('/database', function(req, res) {
connection.connect();
connection.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
  console.log(rows[0].solution);
  res.send('test');
  connection.end();
});
});

但是当我尝试使用浏览器连接到localhost：3000 /数据库时出现此错误：

c:\Users\topsu_000\Documents\webapp\routes\index.js:27
  console.log(rows[0].solution);
                  ^

TypeError: Cannot read property '0' of undefined
    at Query._callback (c:\Users\topsu_000\Documents\webapp\routes\index.js:27:19)
    at Query.Sequence.end (c:\Users\topsu_000\Documents\webapp\node_modules\mysql\lib\protocol\sequences\Sequence.js:96:24)
    at c:\Users\topsu_000\Documents\webapp\node_modules\mysql\lib\protocol\Protocol.js:399:18
    at Array.forEach (native)
    at c:\Users\topsu_000\Documents\webapp\node_modules\mysql\lib\protocol\Protocol.js:398:13
    at nextTickCallbackWith0Args (node.js:420:9)
    at process._tickCallback (node.js:349:13)

我该如何运作？