User Ride Trends with Windows | Dataford Interview Questions

RideFlow wants to analyze how rider activity changes month over month. Write a PostgreSQL query to calculate user-level ride trends over time using window functions.

Requirements

Return one row per user per month for completed rides only.
For each user-month, calculate:
- total completed rides
- total completed fare
- previous month's completed ride count
- month-over-month change in completed rides
- a trend label: growing, declining, or flat
Include users even if they have no matching city record.
Order the final output by user_id and month.

Schema

users

Column	Type	Description
user_idPK	INT	Unique rider identifier
user_name	VARCHAR(100)	Rider full name
signup_date	DATE	Date the rider signed up
city_id	INT	Home city reference

cities

Column	Type	Description
city_idPK	INT	Unique city identifier
city_name	VARCHAR(100)	City name

rides

Column	Type	Description
ride_idPK	INT	Unique ride identifier
user_id	INT	Rider who took the trip
ride_date	DATE	Date of the ride
status	VARCHAR(20)	Ride status such as completed or cancelled
fare_amount	NUMERIC(10,2)	Fare charged for the ride

Your question is User Ride Trends with Windows. Start with the requirements and the three tables in the Question tab.

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