By Michael Nocito , data analyst · Published August 7, 2026 If you want to write SQL against your own data today, install a file-based engine: SQLite if you are learning, DuckDB if your data is already in CSV files. Both give you the whole SQL language. Neither has a server to start, a port to open, or a password to set. Install a server such as PostgreSQL, MySQL or SQL Server when, and only when, more than one person or program needs to read and write the same data at the same time. ...