-- Select all those events that have no event time and belong to the schedule that is assigned to the same usergroup as the user.
SELECT * FROM EVENT 
LEFT OUTER JOIN EVENTTIME ON EVENTTIME_eventTimeID = EVENT_EVENTTIME_eventTimeID 
    WHERE EVENT_rowStatus = 'ACTIVE' 
          AND EVENT_EVENTTIME_eventTImeID =  '-1'
          AND EVENT_SCHEDULE_scheduleID IN 
              (SELECT SCHEDULE_scheduleID FROM SCHEDULE
               LEFT OUTER JOIN 
                    (SELECT BELONGS_USERGROUP_usergroupID AS 'userGroupID' FROM BELONGS WHERE BELONGS_USER_userID = [---USER ID GOES HERE!!!---] )  BELONGS_UG
               ON SCHEDULE_USERGROUP_usergroupID = userGroupID WHERE SCHEDULE_USERGROUP_usergroupID = userGroupID )
    