Theres a lot of documentation and tutorials out there on SQL and it really isn't too difficult. Basically just tables that store data (like infractions for every player), and you send 'queries' to do stuff like read some of the info, update the info, delete stuff, or add new stuff.
What Kryptanite was trying to say is, when you run the query using SQL_Query the result might take a while and make the server lag. Instead you should using something called a threaded query (SQL_TQuery) where you feed it in the query and instead of delaying the server frame or causing lag, it'll just execute a function that you pass it (called callback functions) when its ready.
There are some good examples of this in the thing I posted, and if you want to know more about queries I suggest this:
https://www.w3schools.com/SQL/deFault.asp. You won't need to know everything there, mostly just the important stuff like INSERT, UPDATE and SELECT.