SQL Monthly Location KPIs | Dataford Interview Questions

Write a SQL query to calculate monthly operational KPIs by location, including total volume, average cycle time, and month-over-month change.

Use completed operational records and exclude records without a valid location. Cycle time is the elapsed time between started_at and completed_at in minutes.

Output

One row per location and calendar month with completed activity.
Columns: location_name, month, total_volume, avg_cycle_time_minutes, mom_volume_change, and mom_volume_change_pct.
Show NULL month-over-month values when no prior month exists, and order by location name and month.

Schema

locations

Column	Type	Description
location_idPK	INT	Unique operational location identifier
location_name	VARCHAR(100)	Display name of the operational location
region	VARCHAR(50)	Geographic region containing the location

operational_events

Column	Type	Description
event_idPK	INT	Unique operational event identifier
location_id	INT	Location associated with the event
status	VARCHAR(20)	Current event status
started_at	TIMESTAMP	Timestamp when operational processing began
completed_at	TIMESTAMP	Timestamp when operational processing completed

Your question is SQL Monthly Location KPIs. Start with the requirements and the two tables in the Question tab.

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Problem