Warning: Undefined variable $db_conx in C:\xampp\htdocs\requests.php on line 5

Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, null given in C:\xampp\htdocs\requests.php:5 Stack trace: #0 C:\xampp\htdocs\requests.php(5): mysqli_query(NULL, 'SELECT COUNT(*)...') #1 {main} thrown in C:\xampp\htdocs\requests.php on line 5