How is SQL work in joplin?

[Atom]

I was looking at the markdown editor guide.

and i noticed it accept SQL code.
and it left me confused.

SQL is a code used to draw information from a data base.
so in Joplin what is the data base?

[Daeraxa]

Are you referring to this guide? Markdown Guide | Joplin under the Code Block section?

If so it isn't that the code will directly interface with the DB, the code block is just there to give a monospace font where markdown and other special characters are preserved and not formatted.
SQL is just a common example of the sort of code people might want to store in a note, marking a code fence with SQL just means that it will perform SQL syntax highlighting. Same as if you mark the fence as md, css, js, html etc.

e.g.

SELECT thing FROM thingy
WHERE thing1 = "thing";

let thingy = thing;
console.log(thingy);

<p>thingy</p>
<br>
<span>thing</span>

As for the database, it is just a sqlite database stored in your joplin config folder so yes, you can use SQL to access it, just not directly via Joplin (at least not without modification or plugin/tool)