How do you query hierarchical data (org charts, category trees) in SQL with a recursive CTE?

Hierarchies (org charts, bill-of-materials, category trees) call for recursion, and a self-join reaches only one level down. The signal is the recursive CTE with its anchor plus recursive members, and understanding how it terminates.

Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.