Recursive CTE (Common Table Expressions)

Recursive CTEs are a powerful feature in SQL that allow you to build complex hierarchical queries, retrieve data stored in hierarchical structures or even perform graph traversal. In simple terms, a recursive CTE is a CTE that refers to itself in its own definition, creating a loop that iterates through the data until a termination condition is met.

Note that recursive CTEs can be complex, and it's important to ensure a proper termination condition to avoid infinite recursion. Also, be careful with the use of UNION ALL or UNION, as it may impact the results and the performance of your query.

Learn more from the following resources:

• @article@PostgreSQL - Recursive Query
• @article@PostgreSQL Recursive Query Explained