运用自己的业余时间学习学习node.js+koa+mysql,制作简单点的小例子，代码写的有点随意，我这里只相当于提供一个引子，升华部分还是需要大家自己去成长，相比来说koa要比express好用许多，没事大家可以自己学习学习，多学习一点东西总是好的！
项目地址https://github.com/iopwanglei...

1.使用数据库管理navicat for MySQL 破解版地址

    https://blog.csdn.net/chandddlleerr/article/details/74606548

2.navicat 连接失败解决方案

    https://blog.csdn.net/u013700358/article/details/80306560

3.联合查询

    * user表CREATE TABLE IF NOT EXISTS user (uid int(11) NOT NULL,username varchar(30) NOT NULL,password char(32) NOT NULL) ENGINE=InnoDB DEFAULT CHARSET=utf8;+-----+-----------+----------+| uid | username | password |+-----+-----------+----------+| 1 | 张翰 | 123456 || 2 | 李二蛋 | 1235531 || 3 | 李文凯 | 123455 || 4 | 安小超 | 12311q || 5 | 韩小平 | 1asdas || 6 | 张三 | 123555 |+-----+-----------+----------+* order_goods表CREATE TABLE IF NOT EXISTS order_goods (oid int(11) NOT NULL,uid int(11) NOT NULL,name varchar(50) NOT NULL,buytime int(11) NOT NULL) ENGINE=InnoDB DEFAULT CHARSET=utf8;+-----+-----------+----------+| oid | uid | name | buytime |+-----+-----------+----------+| 1  | 6  | 张翰  | 123456 || 2  | 1  | 李二蛋| 1235531 || 3  | 2  | 李文凯| 123455 |+-----+-----------+----------+* sql的left join 、right join 、inner join之间的区别left join(左联接) 返回包括左表中的所有记录和右表中联结字段相等的记录 right join(右联接) 返回包括右表中的所有记录和左表中联结字段相等的记录inner join(等值连接) 只返回两个表中联结字段相等的行* 内连接查询： select表，字段uid，username[as]使用别名，select order_goods表，字段（和前边一样）inner join 表（order_goods）on 条件 = 匹配条件select user.uid ,user.username as username,order_goods.oid,order_goods.uid,order_goods.name as shopname from user inner join order_goods on user.uid = order_goods.uid;* 外连接 左连接：select 表（user）以左表（user）为主，显示， on 条件select * from user left join order_goods on user.uid = order_goods.uid;* 外连接 右连接：以右表为主显示核对成功的即on的条件成立的SELECT * FROM `user` RIGHT JOIN order_goods on user.uid = order_goods.uid;* 子查询 ： 子查询的关键字包括in、not in、=、!=、exists、not exists等。select * from user where uid in (1,2,3); 查询user表中uid 为1,2,3的数据select * from user where uid in (select uid from order_goods); 查询order_goods表中uid和user表中相同的，在user表中展示* 交叉连接： CROSS JOINSELECT * FROM user CROSS JOIN order_goods; 自行查看展示

4.安装koa等所需

   npm i koa //使用async await 异步须node版本为7.6.0以上npm i koa-routernpm i koa-bodyparser  //解析中间件npm i mysql

5.目录结构

6.config文件下mysql.js 数据库连接池

const mysql = require('mysql');
// 创建连接池
let pool = mysql.createPool({host: '127.0.0.1', // 主机user: 'root',        //  mysql认证用户名password: '789456', //   mysql用户密码port: '3306',       //    端口database: '数据库'
});let query = ( sql, values ) => {return new Promise(( resolve, reject ) => {pool.getConnection(function(err, connection) {if (err) {reject( err )} else {connection.query(sql, values, ( err, res) => {if ( err ) {reject( err )} else {resolve( res )}connection.release()})}})})
}
module.exports = query;

7.路由user_router.js,这里需要调用servse文件中的user_servse.js里面的方法

const router = require('koa-router')();
const user = require('../servse/user_servse.js');
const routers = router.post('/add', user.selectData);
module.exports = routers;

8.路由index.js使用

const router = require('koa-router')();
const user = require('./user_router.js');router.use(user.routes(), user.allowedMethods())module.exports = router;

9.user_servse.js方法，以及sql语句，引入mysql.js

const query = require('../config/mysql.js');
// 新增插入数据查询条件
let insert = 'INSERT INTO `goods` (`oid`, `uid`, `name`, `buytime`) VALUES (?, ?, ?, ?)';const user = {async selectData(ctx) {let data = ctx.request.bodylet userAddParams = [data.oid,data.uid,data.name,data.buytime];if(Object.keys(data).length > 0) {try {await query(insert, userAddParams);ctx.response.body = {status: 200,description: 'ok',result: data}} catch(err) {ctx.response.body = {status: 404}}}}
}
module.exports = user;

10.app.js启动文件

const Koa = require('koa');
const app = new Koa();
const bodyParser = require('koa-bodyparser');
const routers = require('./router/index');// 配置ctx.body解析中间件
app.use(bodyParser())// 初始化路由中间件
app.use(routers.routes()).use(routers.allowedMethods())app.listen(3000);

学习资料 喜欢的童鞋点个赞
1.http://mysql.phpxy.com/75314
2.http://www.manongjc.com/artic...
3.http://www.runoob.com/mysql/m...