Oracle——distinct的用法

--工号，姓名，所属公司id，所属公司，部门id，部门，直属部门,岗位，直接上级，工作地点，职级，安全级别

select distinct a.loginid,a.lastname,a.subcompanyid1,e.subcompanyname,
b.id,
b.departmentname,
sys_connect_by_path(b.departmentname , '\') as a,
c.jobtitlename,
(select lastname from hrmresource where a.managerid=id ),
d.locationname,a.joblevel,a.seclevel
from  hrmresource a ,HrmDepartment b,HrmJobTitles c,HrmLocations d,hrmsubcompany e
where a.departmentid=b.id and a.jobtitle=c.id and a.subcompanyid1=e.id
and a.locationid=d.id and a.status in(0,1,2,3) 
start with b.supdepid =0
connect by prior b.id= b.supdepid 
order by  a.subcompanyid1,b.id,a.loginid