Missing column data in join clause

[eluser]nofearinc[/eluser]
I suppose it's due to ambiguity. I added a select() with required fields above the other join clauses:

Code:

$this->CI->db->select("users.user_id as user_id, username, password, group_name");

I'm able to extract the user_id now. The problem is that I have unpredictable number of fields in both tables so I need the 'select *' statement extracted. Is it possible to do "select users.user_id, *" or something like this in the statement in order to properly retrieve the ID?