Data Engineering Associate with Databricks Practice Exam

How do Views and CTEs differ in SQL?

1. Views can only be temporary

2. CTEs can be accessed across multiple statements

3. Views can be permanent or temporary; CTEs are temporary

4. CTEs require schema enforcement

The correct answer is: Views can be permanent or temporary; CTEs are temporary

Views and Common Table Expressions (CTEs) serve different purposes in SQL, and understanding these differences is crucial for effectively using them in data manipulation and querying. Views are essentially saved queries that can encapsulate complex SQL logic. They can be designed as either permanent or temporary structures. Permanent views exist within the database schema and can be reused across multiple sessions and queries until explicitly dropped. Temporary views, on the other hand, exist only for the duration of the session or transaction in which they were created. In contrast, CTEs are defined within the scope of a single SQL statement. They are inherently temporary and exist only for the duration of the statement that references them. This means that while CTEs allow for wayfinding and reusing complex query logic within a single query, they cannot be accessed once that query has completed execution. The choice that states "Views can be permanent or temporary; CTEs are temporary" accurately captures the essence of how views and CTEs differ. It emphasizes that views can persist beyond a single execution context, allowing for consistent accessibility, while CTEs are a transient construct utilized solely within the confines of a single SQL command.