Mysql PHP extensions?

Question

PHP

Good afternoon.
I put the project: https://github.com/paypal/rest-api-sample-app-php
But I get an error:

The requested PHP extension ext-mysql * is missing from your system. Install or enable PHP's mysql extension.

Tell me what is the ext-mysql extension? And how to put it.
ps php7, LAMP

Answer 1

Missing php-mysql extension
sudo apt-get install php-mysql