SQL Top 10% Purchasing Users | Dataford Interview Questions

How would you write a SQL query to identify the top 10% of purchasing users by region over the last quarter?

Use the previous completed calendar quarter relative to current_date. Include only completed purchases and users assigned to a recognized region.

Output

One row per qualifying user, with region_name, user_id, total_spend, region_user_count, and user_rank
Include the top 10% of purchasing users in each region, retaining at least one user per region
Order by region_name, then user_rank, then user_id

users

Column	Type	Description
user_idPK	INT	Unique purchasing user identifier
user_name	VARCHAR(100)	User display name
region_id	INT	Assigned region identifier

regions

Column	Type	Description
region_idPK	INT	Unique region identifier
region_name	VARCHAR(100)	Region name

purchases

Your question is SQL Top 10% Purchasing Users. Start with the requirements and the three tables in the Question tab.

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