This optional parameter specifies additional SQL columns to fetch with BasicSelect.

You can optionally fetch your own additional columns from the user database when you fetch the password in a similar way to AuthSQL. In this example, you define an additional column in the customer table called maxsessions, which (if not NULL) will be used to set Simultaneous-Use for the user. AuthSelect is the SQL required to select additional columns from customer, so the comma is required.

AuthSelect ,maxsessions
AuthColumnDef 0,Simultaneous-Use,check