Day-1 and Day-7 Cohort Retention

SQLHardSenior level~15 min

Problem

**[Classic — cohort analytics]**

For each signup cohort (grouped by `signup_date`), calculate:
- `cohort_size`: number of users that signed up
- `day1_pct`: % returning on day 1
- `day7_pct`: % returning on day 7

Return `signup_date`, `cohort_size`, `day1_pct`, `day7_pct` (rounded to 2 dp),
ordered by signup_date.

Tables

Example rows — the live problem includes the full dataset.

users

user_id	signup_date

activity

activity_id	user_id	activity_date

Expected output

Your answer should return 3 rows with the columns signup_date, cohort_size, day1_pct, day7_pct.

Starter code (SQL)

SELECT *
FROM users;

Solve this SQL question free

Write SQL and run it instantly in your browser — even on your phone. No signup needed to try.

Solve it now → Create free account

Solution & explanation

Create a free account to unlock the optimal solution, a step-by-step explanation, and the hidden test cases that grade your answer.