PHP Script to Connect to Database and Get List of Departments

<?php

// set header for text content
header('Content-type: text/plain');

// use Dotenv to load database info from .env file
// DB_HOST, DB_USER, DB_PW, DB_NAME
require_once('vendor/autoload.php');
$dotenv = Dotenv\Dotenv::createImmutable(__DIR__);
$dotenv->safeLoad();

// Connecting, selecting database
$mysqli = new mysqli($_ENV['DB_HOST'],$_ENV['DB_USER'],$_ENV['DB_PW'],$_ENV['DB_NAME']);
if ($mysqli->connect_errno) {
    echo "Failed to connect to mysql: ".$mysqli->connect_errno." ".$mysqli->connect_error;
}

// Performing SQL query
$query = 'SELECT DISTINCT department, department_code FROM ext_courses ORDER BY department';
$result = $mysqli->query($query);

// iterating through results
while ($row = $result->fetch_assoc()){
  echo $row['department_code'];
  echo "\t";
  echo $row['department'];
  echo "\n";
}
?>

Output