UNION ALL

How can we combine datasets preserving all rows without deduplication overhead?

Advanced⏱ 3 Minutes⭐ 1750 XP

🤔 THE QUESTION

How can we combine datasets preserving all rows without deduplication overhead?

💡 WHAT IS IT?

UNION ALL concatenates datasets directly while preserving all duplicates, executing much faster.

🎯 WHAT IS IT USED FOR?

High-throughput data ingestion, log merging, historical append pipelines in data lakes.

💻 EXAMPLE

SELECT name
FROM employees
UNION ALL
SELECT name
FROM contractors;

Practice typing production-grade SQL code for UNION ALL.