Some of the advanced stuff has great docs. E.g. SQL Server and its wire protocol. When you need to write client to a language that doesn't have one, the TDS doc

Some of the advanced stuff has great docs. E.g. SQL Server and its wire protocol. When you need to write client to a language that doesn't have one, the TDS doc from Microsoft is amazing. Compare that to e.g. Oracle and you know what I mean. In general SQL Server is such a great product. If you cannot choose PostgreSQL for some reason, make sure your buying manager plays golf with the Microsoft sales people, not with Oracle.