Business Analyst: What are SQL window functions for BA analysis?

1-- Rank sales by region
2SELECT 
3  product,
4  region,
5  sales,
6  RANK() OVER (PARTITION BY region 
7              ORDER BY sales DESC) as rank
8FROM sales_data;
9
10-- Running total
11SELECT 
12  order_date,
13  amount,
14  SUM(amount) OVER (
15    ORDER BY order_date) as running_total
16FROM orders;