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Daily User Retention Query
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Daily User Retention Query

MediumSQL · PostgreSQL

Problem

Write a query to calculate the retention rate of users on a daily basis.

Treat each user's signup date as their cohort date. For each cohort and qualifying activity date, calculate retention as distinct active users divided by the total users who signed up on that cohort date. Ignore activity before signup and activity records that cannot be linked to a user.

Output

  1. One row per cohort date and activity date with qualifying activity.
  2. Columns: cohort_date, activity_date, days_since_signup, cohort_users, retained_users, and retention_rate.
  3. Sort by cohort_date, then activity_date.

Schema

users
ColumnTypeDescription
user_idPKINTUnique user identifier
signup_dateDATEDate the user signed up
user_activity
ColumnTypeDescription
activity_idPKINTUnique activity record identifier
user_idINTUser associated with the activity
activity_dateDATEDate on which the activity occurred
Tablesusersuser_activity
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