SQL queries written against the Northwind database, focused on operational metrics including revenue by category, employee workload, fulfillment speed, and customer inactivity.
| # | Business Question | File |
|---|---|---|
| 1 | Which product category generated the most revenue? | 01_revenue_by_category.sql |
| 2 | Which employee processed the most orders? | 02_top_employees_by_orders.sql |
| 3 | Which shipper has the fastest average fulfillment time? | 03_shipper_fulfillment_speed.sql |
| 4 | Which customers have been inactive for 6+ months? | 04_inactive_customers.sql |
- SQLite / SQLiteOnline.com
- Dataset: Northwind (classic sample business database)
- Beverages is the top revenue category at $92M, nearly 40% ahead of second-place Confections ($66M) — any stockout or supply issue in this category has outsized business impact and should be prioritized.
- Workload is evenly distributed across all 9 employees (1,754–1,908 orders), suggesting no single point of failure in order processing — a sign of healthy operational capacity.
- Shipper choice is not a fulfillment lever — United Package, Federal Shipping, and Speedy Express all average 7.8–7.9 days. If leadership wants to reduce fulfillment time, the bottleneck is elsewhere (warehouse, processing, inventory) — not the carrier.
- 91 customers have been inactive since May 2023 — FISSA Fabrica Inter. Salchichas S.A. (Spain) holds the oldest last order date. Two records show NULL country values, indicating a data quality gap that would need cleaning before any customer outreach campaign.
Beverages drives disproportionate revenue and warrants priority inventory management. Fulfillment speed is consistent across all shippers, meaning carrier negotiations are unlikely to move the needle — operational improvements should focus upstream on order processing and warehouse efficiency instead.