高频题（0）
1. SQL Aggregation and List Aggregation
Write an SQL query to perform a simple group by count aggregation. Additionally, write another SQL query that uses list aggregation to consolidate the names of the top 3 fulfillment centers with the highest count into a single column.
2. Counting Books by Genre from a Nested JSON
Given a nested JSON structure containing book information with fields such as title, author, year, genre, etc., write a Python script to count the number of books in each genre. You can use dictionary comprehension or json_normalize along with pandas DataFrame groupby and either nunique or count methods.
