Challenge: Optimizing Customer Revenue Analysis

Write a query that efficiently analyzes customer revenue using Materialized Views and Common Table Expressions (CTEs) on the retail_data_updated table:

1. Create a Materialized View that pre-aggregates total revenue ('total_amount') for each 'customer_id' and 'customer_country'.
2. Use a CTE to rank customers within each country based on their 'total_revenue'.
3. Query the Materialized View to return the top 5 customers by revenue per country.
4. Sort results by 'customer_country'.

Your query should return these columns:

• 'customer_id' (unique customer identifier);
• 'customer_country' (customer's country);
• 'total_revenue' (sum of 'total_amount' for the customer);