Window Function for Top Containers | Dataford Interview Questions

Write a query using a window function to find the top three heaviest containers loaded onto each vessel at Mediterranean Shipping.

Use the vessel and container loading tables. Exclude containers whose weight is NULL. Assign distinct, deterministic positions by sorting heavier containers first and breaking equal-weight ties by container ID.

Output

One row per selected container, with vessel_id, vessel_name, container_id, weight_kg, and weight_rank.
Include up to three containers per vessel, ordered by vessel_id and weight_rank.

Schema

vessels

Column	Type	Description
vessel_idPK	INT	Unique identifier for the vessel
vessel_name	VARCHAR(100)	Mediterranean Shipping vessel name
registry_port	VARCHAR(100)	Port where the vessel is registered

container_loads

Column	Type	Description
container_idPK	INT	Unique identifier for the container loading record
vessel_id	INT	Vessel carrying the container
container_code	VARCHAR(20)	Container identification code
weight_kg	NUMERIC(10,2)	Container gross weight in kilograms

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Problem