Scenario SQL Question

Find Pairs of Employees in Same Department

Build mastery in Self Joins Hierarchical with this scenario-based SQL challenge and live execution support.

Problem Statement

Find pairs of employees who work in the same department. Exclude self-pairs and avoid duplicate (A,B)/(B,A) pairs by enforcing employee1_id < employee2_id. Skip rows where department_id IS NULL. Return employee1_name, employee2_name, department_id — ordered by department_id, employee1_name, employee2_name.

Relevant Tables

employees

SQL Concepts Used in This Scenario

Strengthen your understanding with these targeted learning topics:

Self JoinsJoins & Relationships
Recursive CTEs for Hierarchical DataSubqueries & CTEs
Common Table ExpressionsSubqueries & CTEs