USERS 
Using the system table USERS, you can determine the following database information, among other things:
·
All defined users with the
database user
class
STANDARD
SELECT
username, groupname
FROM DOMAIN.USERS
WHERE usermode = 'STANDARD'
·
All users who have not
changed their password for over six months
SELECT
username, pwcreatedate, pwcreatetime
FROM DOMAIN.USERS
WHERE pwcreatedate <= subdate (date,183)
·
All users who are members
of a user group and are allowed to log on to the
database instance
several times simultaneously
SELECT
groupname, username, usermode
FROMDOMAIN.USERS
WHERE groupname <> username
AND connectmode = 'MULTIPLE'
·
Name of the database
instance on which the current
database session
was opened. Name of the server on
which this database instance is running.
SELECT
DISTINCT serverdb, servernode
FROM DOMAIN.USERS

Currently active user: see CONNECTEDUSERES