This query analyzes the average sales per month for each product category and compares sales performance across different years. (OVER PARTITION BY)
MonthlySales CTE: Aggregates total sales per month for each product category.
YearlySales CTE: Computes average monthly sales per category per year.
SalesComparison CTE: Compares current year sales with previous year's sales.
Final SELECT Statement: Calculates growth percentage and handles cases with no previous year data.