SQL for Driver Completion Decline | Dataford Interview Questions

Uber Operations needs to identify drivers who completed at least 50 trips during the previous calendar month but had a lower completion rate during the most recent seven-day period. Assume the reporting snapshot date is 2025-03-31.

Write a PostgreSQL query that joins driver details with daily trip metrics.

Requirements

Calculate each driver's monthly completion rate for February 2025.
Calculate each driver's completion rate from March 25 through March 31, 2025.
Return drivers with at least 50 completed trips last month and a strictly lower recent completion rate.
Include driver ID, name, city, both rates, and completed trips for the prior month. Sort by monthly completed trips descending, then driver ID.

A completion rate is completed trips divided by requested trips. Treat a NULL completed-trip value as zero and avoid division by zero.

Schema

drivers

Column	Type	Description
driver_idPK	INT	Unique driver identifier
driver_name	VARCHAR(100)	Driver's full name
city	VARCHAR(50)	Uber operating city
status	VARCHAR(20)	Current driver status

daily_driver_metrics

Column	Type	Description
metric_idPK	INT	Unique daily metric identifier
driver_id	INT	References drivers.driver_id
metric_date	DATE	Date covered by the metric
requested_trips	INT	Trips requested from the driver
completed_trips	INT	Trips completed by the driver

Your question is SQL for Driver Completion Decline. Start with the requirements and the two tables in the Question tab.

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Problem