Leaderboard

I'm not familiar with the ESP32 in particular but usually these micro-controller products are no where near capable of running an SQL database locally. For the ones that have networking capabilities, you can usually get some sort of TCP/IP connection going either via a minimal HTTP server or custom socket setup. It looks like that's what the whole MQTT thing is so that sounds like a good option. For the ones without networking capabilities you'd generally hook them up to a computer via a serial connection and connect to it that way. This is what I've usually done for my occasional Arduino based projects.