What is a CTE in SQL Server and advantages?

What Exactly Is a CTE?

A CTE (Common Table Expression) is like a temporary result set you define inside your query.
Think of it as giving a short name to a subquery, making your SQL cleaner, easier to read, and a lot easier to maintain.

It lives only for the duration of a single SQL execution.

Why Use a CTE? (The Real Advantages)

• Sharper Readability:
  Break down monstrous queries into clear, logical building blocks.

• Simpler Maintenance:
  Fix one CTE block instead of digging through tangled subqueries.

• Reusable Logic:
  Define a CTE once and reuse it multiple times within the same query.

• Flexible Usage:
  You can define a CTE inside functions, stored procedures, triggers, and even views!

• Full Power:
  After defining it, you can SELECT, INSERT, UPDATE, and DELETE from the CTE just like you would with a regular table or view.

Basic Syntax of a CTE:

;WITH CTEName (optional_parameters) AS
(
    SQL Query
)
SELECT * FROM CTEName;