Build a monthly retention curve for new users | Dataford Interview Questions

How to build a monthly retention curve for new users? Cohorted 30, 60, 90 day, 6month, 1 year retention rates using company level table with signupdate and terminationdate ?

Asked in the 1:1 technical stage. Same company table. Use the companies table and treat a company as retained when its termination date is NULL or on or after the relevant retention date.

Output

One row per signup month, ordered chronologically.
Columns: cohort_month, cohort_size, retention_30_day_pct, retention_60_day_pct, retention_90_day_pct, retention_6_month_pct, and retention_1_year_pct.
Retention values should be percentages rounded to two decimal places.

Schema

companies

Column	Type	Description
company_idPK	INT	Unique company identifier
signup_date	DATE	Date the company signed up
termination_date	DATE	Date the company terminated, or NULL if still active

Your question is Build a monthly retention curve for new users. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem