COALESCE

How can we replace NULL values with a default fallback string?

Advanced⏱ 3 Minutes⭐ 1320 XP

🤔 THE QUESTION

How can we replace NULL values with a default fallback string?

💡 WHAT IS IT?

COALESCE returns the first non-NULL expression from its arguments.

🎯 WHAT IS IT USED FOR?

Replacing null phone numbers, default customer names, preventing UI null crashes.

💻 EXAMPLE

SELECT
name,
COALESCE(phone, 'Unknown') AS phone
FROM employees;

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