196. Using helper table for date ranges

This lesson teaches a very important trick when working with date ranges. Let’s examine the results of our retention curve query carefully:

WITH user_activity AS ( SELECT u.user_id, u.created_at::date AS signup_date, e.created_at::date AS activity_date, COUNT(*) AS events_counts FROM mobile_analytics.events u LEFT JOIN mobile_analytics.events e ON e.user_id = u.user_id WHERE u.action = 'signup' GROUP BY 1, 2, 3 ORDER BY signup_date ASC, user_id ASC ) SELECT activity_date, COUNT(DISTINCT(user_id)) AS active_users,...