Find the customer who made the highest payment in 2005.
The highest payment refers to max(amount); 2005 refers to year(paymentDate);
SELECT t2.customerName FROM payments AS t1 INNER JOIN customers AS t2 ON t1.customerNumber = t2.customerNumber WHERE STRFTIME('%Y', t1.paymentDate) = '2005' GROUP BY t2.customerNumber, t2.customerName ORDER BY SUM(t1.amount) DESC LIMIT 1