SQL for Second Highest Value | Dataford Interview Questions

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

Your question is SQL for Second Highest Value. Start with the requirements and the three tables in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem