This article provides a comparison and overview of two different approaches in SQL for managing complex queries, namely Common Table Expression (CTE) and VIEW.

CTE is a temporary construct that exists for the duration of a single query and is particularly useful for recursive queries and reducing redundancy. It is stored in memory during query execution and is not suitable for handling large amounts of data.

CTE does not store statistics or indexes, but it can be used for hierarchical querying and recursive calls.

In contrast, VIEW is a stored SQL query that can be used in multiple queries and is a physical object stored on disk. It offers flexibility and a centralized approach to complex queries by encapsulating complex statements and simplifying queries.

Unlike CTE, VIEW stores the query itself, not the data returned by the query, and can add computed columns.

Both CTE and VIEW are interpreted the same by the Plan Optimizer and can be used to create self-contained code.

CTE vs VIEW

CTEs and views are both useful tools in SQL for managing and simplifying complex queries, but they differ in terms of their duration, storage, and usage in subsequent queries.

A CTE exists for the duration of a single query and is temporary, residing only in memory during query execution. It is suitable for recursive queries and reducing redundancy, but not for dealing with large amounts of data.

On the other hand, a view is a stored SQL query that can be used in multiple queries. It is a physical object stored on disk and can be indexed. Views provide flexibility and a centralized approach to complex queries, encapsulating complex statements and simplifying queries. They are suitable for dealing with large amounts of data and can be used to create self-contained code.

Comparison and Overview

Views and CTEs serve different purposes in database management and offer distinct advantages, such as the ability to store and reuse queries, or perform recursive operations and reduce redundancy in a single query.

CTEs, or Common Table Expressions, are temporary and exist only for the duration of a single query. They are useful for recursive queries and can be referenced multiple times in a query. However, CTEs are not suitable for dealing with large amounts of data as they exist only in memory during query execution and cannot store statistics or indexes.

On the other hand, views are stored SQL queries that can be used in multiple queries. They can be indexed and provide a centralized approach to complex queries. Views encapsulate complex statements and simplify queries, and can be used when dealing with large amounts of data. They are physical objects stored on disk and can add computed columns.

Both CTEs and views have their own advantages and can be used in different scenarios based on the requirements of the database management system.

Use Cases

One potential use case for both CTEs and views is to simplify complex queries and encapsulate them within a centralized and reusable structure.

CTEs can be particularly useful when dealing with recursive queries or when reducing redundancy in queries. They provide a temporary and in-memory solution that exists only for the duration of a single query.

On the other hand, views offer the advantage of being stored on disk and can be used in multiple queries. They provide a more permanent and indexed solution, making them suitable for dealing with large amounts of data. Views also allow for the addition of computed columns, which can further enhance query flexibility.

Overall, both CTEs and views offer a way to centralize and simplify complex queries, but their specific use cases may vary depending on the requirements of the query at hand.