Top Merchant Per Customer by Transaction Value

The marketing analytics team wants to identify each customer's favorite merchant based on total transaction value for targeted partnership offers. For every customer who has made at least one transaction, return their name, email, and the merchant at which they've spent the most in total. If there are ties, return the merchant with the lexicographically smallest name. Include the total amount spent at that merchant. Only include customers who have at least one transaction, and order results by the customer's full name ascending.