Top Sales Regions SQL Join | Dataford Interview Questions

Bain & Company wants to compare sales performance across regional markets. Write a PostgreSQL query that identifies the top-performing regions during the first quarter of 2025.

Requirements

Join sales to customers and regional_mapping using the customer identifier.
Include only sales from January 1 through March 31, 2025, with sale_status = 'Completed' and active customers.
Calculate total revenue and distinct active customers for each region.
Rank regions by total revenue and return the top three ranks, including ties.

Schema

customers

Column	Type	Description
customer_idPK	INT	Unique customer identifier
customer_name	VARCHAR(100)	Customer display name
customer_status	VARCHAR(20)	Customer account status

sales

Column	Type	Description
sale_idPK	INT	Unique sale identifier
customer_id	INT	Customer associated with the sale
sale_date	DATE	Date the sale was recorded
sale_amount	DECIMAL(12,2)	Revenue amount for the sale
sale_status	VARCHAR(20)	Current sale status

regional_mapping

Column	Type	Description
customer_idPK	INT	Mapped customer identifier
region_name	VARCHAR(50)	Assigned sales region

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