I've even worked on a number of projects where a) the unit tests used an in-memory database b) dev environments used mySQL/postgres/SQLite or similar c) product

I've even worked on a number of projects where a) the unit tests used an in-memory database b) dev environments used mySQL/postgres/SQLite or similar c) production used Oracle or SQL server or similar Good luck doing that with hand-coded SQL. But for me 99% of the benefit of using an ORM is compile-time checking of queries. I don't see why in principle that couldn't be possible using raw SQL, but I don't know of any good examples of it.