Percentage by Group

How can we calculate what percentage of the total workforce belongs to each department?

Advanced⏱ 3 Minutes⭐ 1880 XP

🤔 THE QUESTION

How can we calculate what percentage of the total workforce belongs to each department?

💡 WHAT IS IT?

Dividing group counts by the global window sum (SUM(COUNT(*)) OVER ()) computes percentage shares per group.

🎯 WHAT IS IT USED FOR?

Workforce allocation share, departmental percentage distribution, portfolio weightings.

💻 EXAMPLE

SELECT
department_id,
COUNT(*) AS employee_count,
100.0 * COUNT(*) / SUM(COUNT(*)) OVER () AS percentage_of_employees
FROM employees
GROUP BY department_id;

🎯 Mission Objectives

Practice typing production-grade SQL code for Percentage by Group.

✓ Percentage share calculation
✓ SUM(COUNT(*)) OVER ()
✓ Window on aggregate
✓ Distribution analytics

🚀 Start Mission

← Prev (Conditional Aggregation)Next Lesson (Multi-Step Analytical Query) →