Correlated Subquery

How can we find employees earning more than their department average?

Advanced⏱ 3 Minutes⭐ 1130 XP

🤔 THE QUESTION

How can we find employees earning more than their department average?

💡 WHAT IS IT?

A correlated subquery references columns from the outer query, evaluating dynamically for each row.

🎯 WHAT IS IT USED FOR?

Department-relative compensation analysis, peer comparison metrics, row-specific thresholds.

💻 EXAMPLE

SELECT e.name, e.salary
FROM employees e
WHERE e.salary > (
    SELECT AVG(e2.salary)
    FROM employees e2
    WHERE e2.department_id = e.department_id
);

🎯 Mission Objectives

Practice typing production-grade SQL code for Correlated Subquery.

✓ Correlated subquery
✓ Outer query reference
✓ Department-relative average
✓ Advanced filtering

🚀 Start Mission

← Prev (NOT EXISTS)Next Lesson (Basic CTE) →