node连接mysql数据库，并写sql语句操作

node连接mysql数据库，并操作

1.新建package.json文件

{
 "name": "my-project",
 "source": "src/index.html",
 "scripts": {
  "start": "parcel",
  "build": "parcel build",
  "less": "lessc src/css/index.less src/css/index.css"
 },
 "devDependencies": {
  "buffer": "^6.0.3"
 },
 "author": "",
 "license": "ISC",
 "dependencies": {
  "body-parser": "^1.20.2",
  "express": "^4.19.2",
  "mysql": "^2.18.1",
  "nodemon": "^3.0.2"
 }
}

2.新建test.js文件

const express = require('express');
const mysql = require("mysql");
const bodyParser = require('body-parser');

const app = express();
app.use(bodyParser.json()); // 解析post请求
const PORT = 3000; // 设置监听端口

// 连接数据库配置
const db = mysql.createConnection({
  host: 'localhost', // 连接的mysql数据库地址
  user: 'root', // mysql数据库账号
  password: 'root', // mysql数据库密码
  database: 'milk' // mysql具体数据库
})

// 连接数据库  
db.connect(err => {
  if (err) {
    return console.error('error: ' + err.message);
  }
  console.log('Connected to the MySQL server.');
});

app.get('/welcome', async (req, res) => {
  db.query('SELECT * FROM collect', (err, results) => {
    if (err) throw err;
    res.send(results); 
  });
  // 此处还可增删改数据库，当前仅展示了查询
});


app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}.`);
});

3.目录下输入cmd唤起命令窗口，运行npm install，安装依赖
4.运行node test.js命令
5.浏览器输入“http://localhost:3000/welcome”，即可看到查询的数据库数据