SQL for Top Depositors by Sector | Dataford Interview Questions

Write a SQL query to find the top customers by total deposits within each sector at Rabobank. Use the provided sector, customer, and deposit data. Include tied top customers, and treat a customer with no non-null deposit amount as having a total of zero.

Output

One row per top customer within a sector, with sector_name, customer_id, customer_name, total_deposits, and rank_in_sector.
Include every customer tied for the highest total in their sector.
Order by sector_name, total_deposits descending, and customer_id.

Schema

sectors

Column	Type	Description
sector_idPK	INT	Unique sector identifier
sector_name	VARCHAR(100)	Rabobank customer sector name

customers

Column	Type	Description
customer_idPK	INT	Unique customer identifier
customer_name	VARCHAR(150)	Customer display name
sector_id	INT	Sector associated with the customer

deposits

Column	Type	Description
deposit_idPK	INT	Unique deposit record identifier
customer_id	INT	Customer owning the deposit
deposit_amount	DECIMAL(14,2)	Deposit balance for the record

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Problem