WordPress at a glance
function is not described

wpdb::db_version() public WP 2.7.0

Retrieves the MySQL server version.

{} It's a method of the class: wpdb{}

No Hooks.

Return

String/null. Version number on success, null on failure.

Usage

global $wpdb;
$wpdb->db_version();

Changelog

Since 2.7.0 Introduced.

Code of wpdb::db_version() WP 5.5.1

<?php
public function db_version() {
	return preg_replace( '/[^0-9.].*/', '', $this->db_server_info() );
}