I have been looking into the source code of the user_sql app, but adding this seems rather complicated¹, because firstly the UI has to be changed to allow one and two column usernames and secondly some of the queries need to be changed as well. Also, although I have a view that returns the concatenated username, the app only allows databases to be specified,
verifyTable() in lib/helper.php makes sure of it.
Finally I don’t quite understand the specification of the hash as products and not as crypt shemes.
What I would like to ask is how complicated you think implementing this feature (username spans two columns) would be in user_sql.
I looked into creating a new app where I can specify the raw SQL for each user property and while this seems more complicated at first it allows for almost endless possibilities and would be probably a pretty easy app compared to the existing one.
What do you think?
¹I have little experience with php and none with apps for Nextcloud.