npm install --save mysql

const mysql=require('mysql');

//1.连接

//createConnection(服务器, 端口号，用户名, 密码, 库名)

var db=mysql.createConnection({host: 'localhost',port:'', user: 'root',

  password: '', database: ''});

//2.查询

db.query("SELECT * FROM `user_table`;", (err, data)=>{

  if(err)

    console.log('出错了', err);

  else

    console.log('成功了');

    console.log(JSON.stringify(data));

});