Showing posts with label CTE. Show all posts
Showing posts with label CTE. Show all posts

Friday, 6 June 2025

Common Table Expressions - CTEs in PostgreSQL || How to Write CTEs || Po...


In this video, we dive deep into Common Table Expressions (CTEs) in PostgreSQL — a powerful feature that helps you write cleaner, more modular, and efficient SQL queries.

Whether you're a beginner exploring PostgreSQL or an advanced user refining your skills, this tutorial covers everything you need to know about WITH queries, including:

  • ✅ What is a CTE?

  • ✅ Syntax and structure

  • ✅ Benefits of using CTEs

  • ✅ Simple CTEs for temporary data sets

  • ✅ Recursive CTEs for generating sequences or traversing hierarchies

  • ✅ Data-Modifying CTEs using INSERT, UPDATE, and DELETE

  • ✅ Using CTEs with JOINs to simplify complex multi-table queries

  • ✅ Materialization and performance tips

You'll see real-time PostgreSQL examples that demonstrate how CTEs can be applied to real-world scenarios like summarizing data, cleaning up subqueries, and chaining modifications.

📌 This video is part of our PostgreSQL Full Playlist, where we guide you step-by-step from basic concepts to advanced performance optimizations.

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Tuesday, 3 June 2025

VALUES Lists in PostgreSQL Queries || Queries in PostgreSQL || PostgreSQ...


In this video of our PostgreSQL Full Playlist (#41), we take a deep dive into the VALUES clause—a powerful feature that lets you define temporary constant row sets without creating a real table.

We cover a variety of real-world scenarios, including:

  • Basic usage of the VALUES clause

  • Assigning column aliases

  • Using VALUES in INSERT statements (single and multiple rows)

  • Joining VALUES with real tables in the FROM clause

  • Performing bulk updates using VALUES and UPDATE together

  • Working with type casting, such as filtering IP addresses

  • Sorting and slicing result sets using ORDER BY, LIMIT, and OFFSET

Each example is practical, beginner-friendly, and designed to help you build solid SQL skills in PostgreSQL. Whether you're prepping for an interview or strengthening your database knowledge, this tutorial has something for everyone.

🔔 Don’t forget to like, comment, and subscribe to the channel for more hands-on PostgreSQL content.

👉 Next Video: WITH Queries (CTEs) in PostgreSQL

Friday, 23 May 2025

Select Lists in PostgreSQL || Queries in PostgreSQL || Best PostgreSQL T...


🔍 Welcome to the Ultimate PostgreSQL Tutorial Series!
In this video (#37), we dive deep into one of the most crucial parts of any SQL query—the SELECT list. Whether you're a beginner or brushing up your database skills, this tutorial will guide you through the many ways PostgreSQL lets you customize the data you retrieve.

👨‍💻 What You'll Learn:

  • How to select all or specific columns

  • Using table aliases for cleaner queries

  • Creating computed columns with expressions

  • Renaming outputs with column aliases (AS)

  • Eliminating duplicates with DISTINCT and DISTINCT ON

  • Leveraging subqueries, functions, and CASE expressions

  • Working with JSON, arrays, and aggregate functions

  • Using LIMIT, OFFSET, and even SELECT without a FROM clause

  • Advanced techniques like CTEs (Common Table Expressions)

✨ With practical examples, best practices, and performance tips, this tutorial is your go-to guide for mastering SELECT lists in PostgreSQL!

🧠 Next Video: Combining Queries in PostgreSQL – UNION, INTERSECT, EXCEPT
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