Cohort First-Week Return Rate

SQLMediumMid level~15 min

Problem

**[Classic — cohort analytics]**

Group customers by their **signup week** (first order). For each cohort, calculate:
- `cohort_size`: customers in the cohort
- `returned_count`: customers who placed another order within 7 days
- `return_rate`: % returned

Return `cohort_week` (YYYY-WW), `cohort_size`, `returned_count`, `return_rate`
(rounded to 2 dp), ordered by cohort_week.

Tables

Example rows — the live problem includes the full dataset.

orders

order_id	customer_id	order_date

Expected output

Your answer should return 3 rows with the columns cohort_week, cohort_size, returned_count, return_rate.

Starter code (SQL)

SELECT *
FROM orders;

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