Window Functions for Top Units | Dataford Interview Questions

Write a SQL query using window functions such as ROW_NUMBER(), RANK(), or DENSE_RANK() to identify the top-performing business units at Genpact clients.

Use total billable revenue as the performance measure and include tied units at the second rank.

Output

Return client_name, business_unit_name, total_billable_revenue, and performance_rank.
Return the top two ranks for each client, with one row per business unit.
Order by client name, rank ascending, and business unit name.

Schema

clients

Column	Type	Description
client_idPK	INT	Unique client identifier
client_name	VARCHAR(100)	Genpact client name

business_units

Column	Type	Description
business_unit_idPK	INT	Unique business unit identifier
client_id	INT	Client owning the business unit
business_unit_name	VARCHAR(120)	Business unit name

performance_metrics

Column	Type	Description
metric_idPK	INT	Unique performance record identifier
business_unit_id	INT	Business unit measured
metric_month	DATE	Month represented by the record
billable_revenue	NUMERIC(12,2)	Monthly billable revenue

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