title: How should I initialize some code in Nextjs 9.0
body: <p>Using <code>create-next-app</code> create new project like this</p>
  
  <pre><code>npx create-next-app next9.1
  cd next9.1
  tree -I node_modules
  ├── components
  │   └── nav.js
  ├── next.config.js
  ├── package.json
  ├── pages
  │   └── index.js
  ├── static
  │   └── favicon.ico
  └── yarn.lock
  </code></pre>
  
  <p>create <code>/pages/api/index.ts</code> file then client can call <code>/api</code></p>
  
  <p>But I need query some data from mysql, Where and When should I initilize mysql pool without server.js (in nextjs precious version)</p>