Spoke to the recruiter, and a technical screening was set up.

• 5 min: Introduction
• 25 min: SQL (Know your basics: Joins, Aggregation, CTEs, Window functions)
• 25 min: Python (Data structures thoroughly and string manipulation)
• 5 min: Questions

1. Retrieve the top 10 customers who purchased the highest total number of books in 2019, considering only non-refunded sales.

2. Calculate the average total purchase amount, segmented by customer reward membership status and whether the purchase was made during a defined season (after Nov 15) or non-season period.

3. Determine what percentage of total book sales (by revenue) is contributed by the top 5 most expensive books.

4. Identify customers who have made purchases on more than one distinct day and bought a combined total of more than 3 books on their first and last purchase dates.