SQL WITH Clause (CTE) Explained | Common Table Expression in SQL | Recursive CTE | SQL Developer

Описание: Master the SQL WITH Clause (CTE) in SQL Developer — learn how to write Simple, Multiple, Recursive CTEs, and how to use them for complex queries. Perfect for interviews & real-time SQL practice.

Learn everything about the WITH Clause (Common Table Expression or CTE) in SQL in this detailed tutorial!
In this video, we’ll understand how to use CTE in SQL Developer with real-world examples — including Simple, Multiple, Recursive, and Window Function CTEs.

We’ll cover step-by-step:

What is a Common Table Expression (CTE)

How to write a WITH clause

Simple CTE Example

Multiple CTE Example

Recursive CTE Example

CTE with Window Functions

Advantages of CTE

Real-time use cases in data engineering

📘 SQL Topics Covered:

WITH Clause Syntax

Subquery Replacement using CTE

Hierarchical and Recursive Queries

Top N Analysis (using DENSE_RANK)

Query Optimization and Readability

💡 Supported Databases:
SQL Server | Oracle | PostgreSQL | MySQL 8+ | Snowflake | BigQuery

👨‍💻 Example Queries Used:
1️⃣ Employees earning more than average salary
2️⃣ High-paying departments
3️⃣ Employee hierarchy (recursive CTE)
4️⃣ Top 3 salaries per department


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