At least some databases I've used have parsed out constants in the client library code and submitted prepared statements to the server, passing those constants in. That meant that the server got better use out of its query cache; on the server side, those are the same query.

Not sure which ones if any do this today, the optimisation might no longer be relevant - I spotted DBs doing this 10 years ago when CGIs that didn't bother with prepared statements were rife.