ERROR:Pleaseinstallmysql2packagemanually安装和使用sequelize出现这个问题时1.可能没有安装mysql2包解决方法：yarnaddmysql22.可能是webpack无法识别解决办法:yarnaddwebpack-node-externals在webpack.config.js中添加：constnodeExternals=require('webpack-node-externals')module.exports={...externals:[nodeExternals()]}到webpack外部扩展（外部）
