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SQL • LESSON 120

COALESCE Multiple Values

How can we fallback through multiple contact methods?

Advanced3 Minutes1330 XP
🤔 THE QUESTION

How can we fallback through multiple contact methods?

💡 WHAT IS IT?

COALESCE evaluates sequential arguments from left to right, returning the first non-NULL entry.

🎯 WHAT IS IT USED FOR?

Cascading contact lookups (mobile -> home -> email -> fallback), tiered attribute resolution.

💻 EXAMPLE
SELECT
name,
COALESCE(phone, email, 'No Contact') AS contact
FROM employees;

🎯 Mission Objectives

Practice typing production-grade SQL code for COALESCE Multiple Values.

  • Cascading fallback
  • Multi-column COALESCE
  • Contact prioritization
  • Resilient data projection