Skip to main content
SQL โ€ข LESSON 166

Combining Different Sources

How can we identify all unique customers across online and in-store channels?

Advancedโฑ 3 Minutesโญ 1790 XP
๐Ÿค” THE QUESTION

How can we identify all unique customers across online and in-store channels?

๐Ÿ’ก WHAT IS IT?

UNION across disparate transactional tables generates a unified unique customer identifier pool.

๐ŸŽฏ WHAT IS IT USED FOR?

Omnichannel customer unification, master data management, total customer base sizing.

๐Ÿ’ป EXAMPLE
SELECT customer_id
FROM online_orders
UNION
SELECT customer_id
FROM store_orders;

๐ŸŽฏ Mission Objectives

Practice typing production-grade SQL code for Combining Different Sources.

  • โœ“ Omnichannel union
  • โœ“ Cross-source deduplication
  • โœ“ Master customer ID list
  • โœ“ Data lake integration