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SQL • LESSON 30

NULL Handling with COALESCE

How do we handle missing or NULL values cleanly with default fallbacks?

Advanced3 Minutes470 XP
🤔 THE QUESTION

How do we handle missing or NULL values cleanly with default fallbacks?

💡 WHAT IS IT?

COALESCE returns the first non-NULL expression from its argument list.

🎯 WHAT IS IT USED FOR?

Data sanitization, preventing NULL propagation in reports, default text fallbacks.

💻 EXAMPLE
SELECT
name,
COALESCE(department, 'Not Assigned')
AS department
FROM employees;

🎯 Mission Objectives

Practice typing production-grade SQL code for NULL Handling with COALESCE.

  • COALESCE
  • NULL safety
  • Default values
  • Data cleaning