Your question is Compare Region Performance Across Months. Start with the requirements and the one table on the right.
Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.
You are given monthly performance data for delivery regions. Write a PostgreSQL query that compares each region’s current month performance to its previous month using a self-join. Return only months where a prior month exists, along with the month-over-month change in orders and revenue.
| Column | Type | Description |
|---|---|---|
| region_id | INT | Region identifier |
| region_name | VARCHAR(100) | Region name |
| month_start | DATE | First day of the month |
| orders_completed | INT | Completed orders in the month |
| gross_revenue | NUMERIC(12,2) | Gross revenue for the month |