Monday, 26 May 2025

Combining Queries in PostgreSQL || UNION, INTERSECT, EXCEPT || Best Post...


Welcome to another powerful episode of our PostgreSQL tutorial series! In Video #38, we dive deep into Combining Queries in PostgreSQL using the essential set operators: UNION, INTERSECT, and EXCEPT.

These operators are invaluable when working with multiple result sets. You'll learn:

  • How to combine query results with UNION and UNION ALL

  • How to find common records across result sets using INTERSECT

  • How to exclude records using EXCEPT

  • The importance of query compatibility and proper use of parentheses

  • How to retain or eliminate duplicates using the ALL keyword

  • Practical examples with Employees and Departments tables

We also cover operator precedence, the role of LIMIT and ORDER BY, and how subqueries and aliasing help you write cleaner, more accurate queries.

💡 Whether you're preparing for interviews, learning PostgreSQL for your job, or building data-driven apps, this tutorial is packed with hands-on examples and key tips that will help you query smarter and faster.

🔥 Don’t forget to like, subscribe, and hit the bell icon for more awesome database tutorials every week!

📌 Next up: Sorting Rows in PostgreSQL using ORDER BY!

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