Average Swipes Last Month | Dataford Interview Questions

Your question is Average Swipes Last Month. Start with the requirements and the two tables on the right.

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Problem

Tinder's Data Science team wants to measure average user engagement during the most recently completed calendar month. Write a PostgreSQL query that calculates the average number of swipes per Tinder user during that month.

Requirements

Include every user in the calculation, including users who made zero swipes during the month.
Define the period as the previous calendar month, from its first instant through the first instant of the current month.
Return one row containing the average swipe count per user, with the output column named average_swipes_per_user.

Schema

users

Column	Type	Description
user_idPK	INT	Unique Tinder user identifier
display_name	VARCHAR(100)	User's display name

swipes

Column	Type	Description
swipe_idPK	INT	Unique swipe event identifier
user_id	INT	User who performed the swipe
target_user_id	INT	User profile that was swiped on
swipe_direction	VARCHAR(10)	Swipe action, such as like or pass
swiped_at	TIMESTAMP	Timestamp when the swipe occurred