One post tagged with "SQL"

Have you ever needed to query a data structure where you didn't know how deep the relationships went? Think of an organizational chart, a complex product assembly (Bill of Materials), or a nested comment thread like Hacker News.

Standard SQL joins fail here because they require you to know the number of levels upfront. Enter the Recursive Common Table Expression (CTE)—a powerful tool that allows a query to reference itself, iterating through levels until a termination condition is met.

In this guide, we’ll explore why recursive CTEs are a game-changer, how to implement them in BigQuery, and the specific architectural patterns required to make them work seamlessly in Looker.