nodejs安装了mysql找不到库?报错

执行前先安装了mysql模块

npm install mysql

执行完后在D:\nodejs\node_modules中生成了一个mysql目录，这个目录里面还有一个npm目录

D:\nodejs就是nodejs安装的目录

test.js文件如下

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

connection.connect();
//查询
connection.query('select * from `test`', function(err, rows, fields) {
    if (err) throw err;
    console.log('查询结果为: ', rows);
});
//关闭连接
connection.end();

node test.js之后报错

module.js:327
    throw err;
    ^

Error: Cannot find module 'mysql'
    at Function.Module._resolveFilename (module.js:325:15)
    at Function.Module._load (module.js:276:25)
    at Module.require (module.js:353:17)
    at require (internal/module.js:12:17)
    at Object.<anonymous> (E:\nodejs\yy.js:1:75)
    at Module._compile (module.js:409:26)
    at Object.Module._extensions..js (module.js:416:10)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Function.Module.runMain (module.js:441:10)

按照网上找的资料，将npm按照的mysql放到node_modules目录下不行，windows/system32下也不行，设置了NODE_PATH还是不行(执行报错，是另外一个错误了)

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

connection.connect();
//查询
connection.query('select * from `test`', function(err, rows, fields) {
    if (err) throw err;
    console.log('查询结果为: ', rows);
});
//关闭连接
connection.end();