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If multiple CTEs are required, initiate each subsequent expression with a comma and repeat steps 2-4.

Define the query to produce the desired result set.

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Provide a name for the result soon-to-be defined query.

Performing the same calculation multiple times over across multiple query components.

An alternative to creating a view in the database.

Needing to reference a derived table multiple times in a single query.

This reduction in complexity is achieved by deconstructing ordinarily complex queries into simple blocks to be used, and reused if necessary, in rewriting the query. How are CTEs helpful?ĬTEs, like database views and derived tables, enable users to more easily write and maintain complex queries via increased readability and simplification. This article will focus on non-recurrsive CTEs. To read the full document, click the button: Download the PDF.

Much like a derived table, the result of a CTE is not stored and exists only for the duration of the query. To learn more about how BigQuery works, see the BigQuery documentation. What are Common Table Expressions (CTEs)?Ī Common Table Expression (CTE) is the result set of a query which exists temporarily and for use only within the context of a larger query.