User Element Prefilter

[p.stahl]

I have a list with a user-element and other fields. In the form I can select the user per dropdown(user Element). Unfortunately, in the drop-down box, all users who are registered. Is there a way to list only user from a user group there?

 

[troester]

Use a dbjoin element linking to #__users instead of the user element and set your condition in data-where.

 

[p.stahl]

Ok, when I should do this with the dbjoin, how would the query look in the data-where?
Unfortunately, I am not (yet) in sql firm.

Thanks