CASE with NULL

How can we classify employees who have no manager?

Advanced⏱ 3 Minutes⭐ 1280 XP

🤔 THE QUESTION

How can we classify employees who have no manager?

💡 WHAT IS IT?

WHEN column IS NULL inside CASE handles missing or unassigned foreign keys with descriptive labels.

🎯 WHAT IS IT USED FOR?

Executive hierarchy classification, identifying unassigned work orders, null handling.

💻 EXAMPLE

SELECT
name,
CASE
    WHEN manager_id IS NULL THEN 'Top Level'
    ELSE 'Has Manager'
END AS hierarchy_level
FROM employees;

Practice typing production-grade SQL code for CASE with NULL.