select distinct cch.emp_person_id 
from cmp_cwb_hrchy cch, cmp_cwb_person_info ccpi
where ccpi.WS_MGR_PERSON_EVENT_ID=cch.MGR_PERSON_EVENT_ID
and ccpi.PERSON_EVENT_ID=cch.EMP_PERSON_EVENT_ID
and ccpi.assignment_id=cch.emp_assignment_id
and ccpi.WS_MGR_ASSIGNMENT_ID=cch.MGR_ASSIGNMENT_ID

/现在我想加上解码或case语句。条件是：如果mgr\u id参数传递manager\u id和lvl\u num=1（对于直接下属），则应显示cch.emp\u person\u id，否则应传递所有员工，表示不考虑lvl\u num=1。/