how to create 2 site with sharing db

Sharing of data base on 2 site was a great challenge. But there are many ways to that. Just prepare a data base and the data base user.
*create and modify site configuration and duplicate settings folder.
cp –R default/ https://www.example.com.site_1
dru@/var/www/drupal/sites: cp –R default/ https://www.example.com.site_2.

Also use MYSQL method.From there you can see syntax and can view them.

I hope it can help a lot.
https://sabetsu.com/