There's some good stuff in here. I didn't know about the issues an aggregation in a CTE can cause and haven't used EXISTS much. Regarding recursive CTEs, you m

There's some good stuff in here. I didn't know about the issues an aggregation in a CTE can cause and haven't used EXISTS much. Regarding recursive CTEs, you might be interested in how DuckDb evolved them with USING KEY: https://duckdb.org/2025/05/23/using-key https://duckdb.org/2025/05/23/using-key