SQL for Second Highest Value | Dataford Interview Questions

Your question is SQL for Second Highest Value. Start with the requirements and the three tables on the right.

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Problem

NeenOpal Canada wants a workforce age analysis across its Canadian offices. Write a PostgreSQL query to identify employees with the second-highest distinct age as of 2026-01-01.

Requirements

Consider only employees whose employment status is Active and whose office is in Canada.
Exclude employees with a missing date of birth.
Calculate age using PostgreSQL date functions and return every employee tied at the second-highest distinct age.
Include the employee's department and office when available.
Be prepared to explain at least two alternative approaches, such as DENSE_RANK(), a distinct-age subquery, or a MAX()-based approach.

Schema

employees

Column	Type	Description
employee_idPK	INT	Employee identifier
full_name	VARCHAR(100)	Employee full name
date_of_birth	DATE	Employee date of birth
employment_status	VARCHAR(20)	Current employment status
department_id	INT	Reference to the employee department
office_id	INT	Reference to the employee office

departments

Column	Type	Description
department_idPK	INT	Department identifier
department_name	VARCHAR(100)	Department name

offices

Column	Type	Description
office_idPK	INT	Office identifier
office_name	VARCHAR(100)	Office name
country	VARCHAR(50)	Office country