SQL Inventory Turnover Analysis

I have a full year of inventory transactions sitting in a PostgreSQL database and I need clear, reliable turnover rates for every SKU. Your task is to write clean, well-commented SQL that:

• pulls the necessary data for the last calendar year
• calculates inventory turnover (cost of goods sold ÷ average inventory value) at SKU, category, and warehouse levels
• highlights outliers and slow-moving items

Alongside the query set, I would like a short narrative that explains the key findings and offers any quick-win recommendations you spot.

Acceptance criteria
• Scripts run as-is in our staging environment and match sample figures I will provide
• Results are delivered in both raw table form and a concise summary (no more than two pages)

Let me know your approach and how soon you can deliver.