How to Write Complex Queries in Apache Spark SQL Using CTE (WITH Clause)

This guide explains how Spark SQL's WITH clause (CTE) improves query readability, reusability, and performance, with real-world examples and best use cases.

Apache Spark SQL uses SQL capabilities to process large-scale structured data. One powerful feature in modern SQL is the WITH clause, supported in Spark SQL as Common Table Expressions (CTE). CTE offers a more organized, readable, and often more efficient way to build complex queries. This article will explain what CTE is, why it is valuable in Spark SQL, and explore its syntax with practical examples.

What is a Common Table Expression (CTE)?

A Common Table Expression, or CTE, is a named, temporary result set that you define within a single SQL statement. It's like a temporary, virtual table that only exists while the query is running. A CTE starts with the WITH clause, followed by one or more named sub-queries ...