Performance Features

Master two important concepts for building efficient and maintainable queries in BigQuery: materialized views and common table expressions (CTEs). Both tools help improve performance and readability when working with large datasets and complex query logic.

Materialized views store precomputed query results and automatically refresh when the underlying data changes. They are especially useful for queries that run frequently, such as dashboards that update every few minutes.

Materialized views are designed to:

• Reduce query execution time and compute cost;
• Update only when source data changes;
• Support near real-time and streaming data;
• Automatically replace base tables in queries when possible, improving performance transparently.

Materialized views work best when:

• Queries are executed often with similar logic;
• Data changes incrementally;
• Fresh results are required without reprocessing full datasets.

Common table expressions (CTEs), defined using the WITH clause, create temporary result sets within a single query. They allow complex logic to be broken into clear, reusable steps.

CTEs are useful because they:

• Make queries easier to read and understand;
• Improve structure compared to deeply nested subqueries;
• Simplify step-by-step data transformations;
• Help maintain and modify queries over time.

CTEs are a strong choice when you need to organize complex transformations or reuse intermediate logic within the same query.