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Compare Signup Cohorts by Retention

MediumWindow FunctionsDate FunctionsCTEs

Problem

StreamWave wants to compare how different signup cohorts behave after registration. Write a SQL query to measure 30-day engagement by monthly signup cohort.

Requirements

Define each user's cohort as the month of their signup_date.
For each cohort month, calculate:
- total users in the cohort
- users with at least one session_start event within 30 days of signup
- the percentage of engaged users in the cohort
Return one row per cohort month.
Order results by cohort month ascending.

Table Definitions

`users`

Column	Type	Description
user_id	INT	Unique user identifier
signup_date	DATE	Date the user registered
acquisition_channel	VARCHAR(50)	Marketing channel that acquired the user

`events`

Column	Type	Description
event_id	INT	Unique event identifier
user_id	INT	User who generated the event
event_type	VARCHAR(50)	Event name
event_date	DATE	Date of the event

Problem

StreamWave wants to compare how different signup cohorts behave after registration. Write a SQL query to measure 30-day engagement by monthly signup cohort.

Requirements

Define each user's cohort as the month of their signup_date.
For each cohort month, calculate:
- total users in the cohort
- users with at least one session_start event within 30 days of signup
- the percentage of engaged users in the cohort
Return one row per cohort month.
Order results by cohort month ascending.

Table Definitions

`users`

Column	Type	Description
user_id	INT	Unique user identifier
signup_date	DATE	Date the user registered
acquisition_channel	VARCHAR(50)	Marketing channel that acquired the user

`events`

Column	Type	Description
event_id	INT	Unique event identifier
user_id	INT	User who generated the event
event_type	VARCHAR(50)	Event name
event_date	DATE	Date of the event

Practice SQL

PostgreSQL

Open on desktop for the full SQL editor with syntax highlighting and autocomplete.

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Compare User Retention by CohortMedium

Weekly Signup Cohort RetentionMedium Monthly User Engagement Trend AnalysisMedium

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Compare Signup Cohorts by Retention

MediumWindow FunctionsDate FunctionsCTEs

Problem

StreamWave wants to compare how different signup cohorts behave after registration. Write a SQL query to measure 30-day engagement by monthly signup cohort.

Requirements

Define each user's cohort as the month of their signup_date.
For each cohort month, calculate:
- total users in the cohort
- users with at least one session_start event within 30 days of signup
- the percentage of engaged users in the cohort
Return one row per cohort month.
Order results by cohort month ascending.

Table Definitions

`users`

Column	Type	Description
user_id	INT	Unique user identifier
signup_date	DATE	Date the user registered
acquisition_channel	VARCHAR(50)	Marketing channel that acquired the user

`events`

Column	Type	Description
event_id	INT	Unique event identifier
user_id	INT	User who generated the event
event_type	VARCHAR(50)	Event name
event_date	DATE	Date of the event

Problem

StreamWave wants to compare how different signup cohorts behave after registration. Write a SQL query to measure 30-day engagement by monthly signup cohort.

Requirements

Define each user's cohort as the month of their signup_date.
For each cohort month, calculate:
- total users in the cohort
- users with at least one session_start event within 30 days of signup
- the percentage of engaged users in the cohort
Return one row per cohort month.
Order results by cohort month ascending.

Table Definitions

`users`

Column	Type	Description
user_id	INT	Unique user identifier
signup_date	DATE	Date the user registered
acquisition_channel	VARCHAR(50)	Marketing channel that acquired the user

`events`

Column	Type	Description
event_id	INT	Unique event identifier
user_id	INT	User who generated the event
event_type	VARCHAR(50)	Event name
event_date	DATE	Date of the event

Practice SQL

PostgreSQL

Open on desktop for the full SQL editor with syntax highlighting and autocomplete.

Up next

Compare User Retention by CohortMedium

Weekly Signup Cohort RetentionMedium Monthly User Engagement Trend AnalysisMedium

Next question

Compare Signup Cohorts by Retention | Dataford Interview Questions