[SQL문제풀기 - Advent of SQL 2025 🎅] A/B 테스트를 위한 버킷 나누기 2

문제

solvesql.com

https://solvesql.com/problems/ab-testing-buckets-2/

내가 작성한 정답

MySQL, PostgreSQL, SQLite

with a as (select *,case when customer_id%10=0 then 'A' else 'B' end bucket 
          from transactions),
     b as (select customer_id, count(transaction_id) tr, sum(total_price) pr, bucket
           from a
           where not is_returned
           group by customer_id, bucket)
select bucket, 
       count(distinct customer_id) user_count,
       round(avg(tr),2) avg_orders,
       round(avg(pr),2) avg_revenue
from b
group by bucket;