Common Table Expressions (CTEs), often called CTEs, are a powerful feature in SQL that allows you to define a temporary named result set within a single SQL statement. Think of them as reusable subqueries, but with a few key advantages. Instead of embedding a complex subquery within a larger query, you can define a CTE once and then reference it multiple times within the same statement. This significantly improves readability and maintainability, especially for intricate queries. CTEs are particularly useful when you need to perform the same calculation or filtering multiple times within a query. They also help to organize your code, making it easier to understand and debug. A well-structured CTE can make a complex query much more manageable and easier to follow. For example, if you need to calculate the average sales for each product category and then filter those results, a CTE can help you break down the process into smaller, more understandable steps.