SQL for Weekly Inventory Turnover | Dataford Interview Questions

Write a SQL query to calculate weekly inventory turnover by store at Walmart and rank stores by turnover within each region.

Use the provided store, inventory snapshot, and sales transaction data for the week beginning January 6, 2025. Include active stores with inventory records for the week, including stores with no qualifying sales.

Output

One row per active store and week
Columns: week_start, region, store_id, store_name, cogs, avg_inventory_value, turnover, and regional_rank
Turnover is cost of goods sold divided by average inventory value
Sort by region, regional_rank, then store_id

Schema

stores

Column	Type	Description
store_idPK	INT	Unique Walmart store identifier
store_name	VARCHAR(100)	Store display name
region	VARCHAR(50)	Operational region containing the store
is_active	BOOLEAN	Whether the store is currently active

inventory_snapshots

Column	Type	Description
snapshot_idPK	INT	Unique inventory snapshot identifier
store_id	INT	Store associated with the snapshot
snapshot_date	DATE	Date of the inventory measurement
inventory_value	NUMERIC(14,2)	Inventory value at the snapshot date

sales_transactions

Column	Type	Description
transaction_idPK	INT	Unique sales transaction identifier
store_id	INT	Store where the sale occurred
sale_date	DATE	Date of the sale
quantity	INT	Units sold
unit_cost	NUMERIC(10,2)	Cost per unit sold

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