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Introduction: The Art of Recursion in SQL
SQL, a language primarily designed for managing structured data, might not seem like the ideal candidate for handling hierarchical or recursive data structures. However, PostgreSQL breaks this mold by offering powerful support for recursive queries. In this blog post, we embark on a journey through the realm of recursive queries, beginning with the fundamentals and culminating in practical applications that can transform how you work with hierarchical data.
Section 1: The Recursive CTE — Your Gateway to Recursion
At the core of recursive queries in PostgreSQL is the Recursive Common Table Expression (CTE). This special CTE type enables a query to refer back to itself, creating a loop that iteratively processes data. Here’s the basic structure of a recursive CTE:
