MoM Growth Rate for Vehicle Production | Dataford Interview Questions

Write a query to find the month-over-month growth rate of vehicle production using a hypothetical manufacturing database.

Use the production_records and vehicle_models tables. Treat NULL production units as zero. Include every month with recorded production, including months without a directly preceding month.

Output

One row per production month
Columns: month_start, total_produced, previous_month_produced, and growth_rate_pct
Return growth as a percentage rounded to two decimal places; use NULL when no prior calendar month exists or prior production is zero
Order chronologically by month_start

Schema

production_records

Column	Type	Description
record_idPK	INT	Unique production record identifier
model_id	INT	Vehicle model reference
production_date	DATE	Date on which vehicles were produced
units_produced	INT	Number of vehicles produced in the record

vehicle_models

Column	Type	Description
model_idPK	INT	Unique vehicle model identifier
model_name	VARCHAR(100)	Vehicle model name

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