Oh3 widget and MySQL database, a few questions

I’m trying to find out what is possible with openhab3 and eg a MySQL database.

I would like to certain data that I call up via json written into a database. To display these in a widget, e.g. with an oh repeater.

Is it possible to have certain data written into an SQL database?
And is it possible to display this data in widgets without having to write it in items? Or in temporary items?

If so, can someone give me an example?

Related thread from a few minutes ago

You can write what you like with some external script.

You can use a webview or similar to display the results of some external script.

i take a look at it, gives perhaps a example how it looks with a webview?