Second-Highest Value Query | Dataford Interview Questions

Business Context

Ahu Technologies wants to identify the second-highest transaction value recorded by its Platform department. Duplicate transaction values must count as one distinct value.

Task

Write a PostgreSQL query that returns the second-highest distinct transaction_value for the department named Platform.

Requirements

Join transactions to departments using department_id.
Restrict results to the Platform department.
Ignore NULL transaction values and treat duplicate values as one distinct ranking level.
Return one column named second_highest_transaction_value. Return no rows if fewer than two distinct values exist.

Schema

departments

Column	Type	Description
department_idPK	INTEGER	Unique department identifier
department_name	VARCHAR(100)	Department name used for filtering

transactions

Column	Type	Description
transaction_idPK	INTEGER	Unique transaction identifier
department_id	INTEGER	Department associated with the transaction
transaction_value	NUMERIC(12,2)	Monetary value of the transaction

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