There have been some projects to develop SSDs that natively present a key-value storage interface, and standardization of that is pretty far along. So those dri

There have been some projects to develop SSDs that natively present a key-value storage interface, and standardization of that is pretty far along. So those drives can function as a backend for eg. a RocksDB substitute with a minimal software frontend. But a full SQL database engine on the SSD would fall under the umbrella of computational storage, and so far everyone with the resources to put any of that into production has datasets that don't fit on a single drive. So there's less utility in having the drive speaking proper SQL, but a lot of active research into how to usefully offload some of the DB work onto compute resources that reside on the SSD itself. (Also, microcontroller is a bit odd to use to refer to the main controller chip inside a SSD, especially a high-end enterprise SSD. It gives a completely misleading indication of scale.)