DuckDB? https://duckdb.org/2024/03/29/external-aggregation.html https://duckdb.org/2024/03/29/external-aggregation.html https://duckdb.org/2021/06/25/querying

DuckDB? https://duckdb.org/2024/03/29/external-aggregation.html https://duckdb.org/2024/03/29/external-aggregation.html https://duckdb.org/2021/06/25/querying-parquet.html https://duckdb.org/2021/06/25/querying-parquet.html If your DB is mysql or postgres, then you could read a stream from parquet, transform inline and write out to your DB https://duckdb.org/2024/01/26/multi-database-support-in-duckdb.html https://duckdb.org/2024/01/26/multi-database-support-in-duck... And an unrelated, but interesting read about the parquet bomb https://duckdb.org/2024/03/26/42-parquet-a-zip-bomb-for-the-big-data-age.html https://duckdb.org/2024/03/26/42-parquet-a-zip-bomb-for-the-...