Please calculate the average total price of shipped orders from German customers.
average total price = DIVIDE(MULTIPLY(quantityOrdered, priceEach)), COUNT(orderNumber)); German is a nationality of country = 'Germany'; shipped orders refers to status = 'Shipped';
SELECT SUM(T3.quantityOrdered * T3.priceEach) / COUNT(T2.orderNumber) FROM customers AS T1 INNER JOIN orders AS T2 ON T1.customerNumber = T2.customerNumber INNER JOIN orderdetails AS T3 ON T2.orderNumber = T3.orderNumber WHERE T2.status = 'Shipped' AND T1.country = 'Germany'