引入模块

const mysql = require('mysql');
const http = require('http');
const url = require('url');
const querystring = require('querystring');

创建http服务器

let server = http.createServer((req, res) => {
    if (req.url == "/favicon.ico") {
        res.end("");
        return
    }
    //如果地址包含“reg/add”则进行添加操作
    if (/reg\/add/.test(req.url)) {
        let {
            username,
            password,
            phone
        } = url.parse(req.url, true).query;

        //创建mysql实例
        var connection = mysql.createConnection({ 
            host: 'localhost',
            user: 'root',
            password: 'root',
            database: 'class'
        });
        //连接数据库
        connection.connect();
        //添加数据 
        let sql = `insert user (username,password,phone) values('${username}','${password}','${phone}')`;
        connection.query(sql, function(error, results, fields) {
                //有错误则抛出
                if (error) throw error;
                res.end('add success');
        })
    
 //查询数据库 
connection.query('SELECT * from user', function (error, results, fields) {
  //有错误则抛出
  if (error) throw error;
  // console.log('The solution is: ', results);  //查询结果
  let res = [];
  results.forEach(ele => {
      //1.使用JSON.stringify转为合法的JSON串 2.使用JSON.parse转为可访问的js对象
      res.push(JSON.parse(JSON.stringify(ele)));
  })
  console.log(res);
});

        //断开数据库连接
      connection.end();
    }
}).listen('1234')

注意事项：

- 更新-update
update 表名 set key=value,key=value where 条件;
`UPDATE user SET username='admin'; `

- 删除-delete
DELETE FROM 表名 where 条件;
`DELETE from user where id = 12;`  -- DELETE要大写

- 查询-select
select * from 表名
`select * from user;`