query("SELECT COUNT(*) as count FROM students")->fetch(PDO::FETCH_ASSOC)['count'] ?? 0;
$coursesCount = $conn->query("SELECT COUNT(*) as count FROM courses")->fetch(PDO::FETCH_ASSOC)['count'] ?? 0;
$usersCount = $conn->query("SELECT COUNT(*) as count FROM users")->fetch(PDO::FETCH_ASSOC)['count'] ?? 0;
$totalPayments = $conn->query("SELECT IFNULL(SUM(amount_paid),0) as totalPayments FROM payments")->fetch(PDO::FETCH_ASSOC)['totalPayments'] ?? 0;
$totalDiscounts = $conn->query("SELECT IFNULL(SUM(discount), 0) as totalDiscounts FROM payments")->fetch(PDO::FETCH_ASSOC)['totalDiscounts'] ?? 0;
$totalExpenses = $conn->query("SELECT IFNULL(SUM(amount), 0) as totalExpenses FROM expenses")->fetch(PDO::FETCH_ASSOC)['totalExpenses'] ?? 0;
$totalRemaining = $conn->query("
SELECT
IFNULL(SUM(c.price), 0) - (
SELECT IFNULL(SUM(amount_paid + discount), 0)
FROM payments
) AS total_remaining
FROM enrollments e
JOIN courses c ON e.course_id = c.id
")->fetch(PDO::FETCH_ASSOC)['total_remaining'] ?? 0;
$profit = $totalPayments - $totalExpenses;
?>
