select case when connect_by_isleaf = 1 then 0
            when level = 1             then 1
            else                           -1
       end as status, 
       level, 
       "ENAME" as title, 
       null as icon, 
       "EMPNO" as value, 
       "JOB" as tooltip, 
       'f?p=&APP_ID.:7:'||:APP_SESSION||'::::P7_EMPNO,P21_SELECTED_NODE:'||"EMPNO"||','||"EMPNO" as link 
from "#OWNER#"."WWV_DEMO_EMP"
start with "MGR" is null
connect by prior "EMPNO" = "MGR"
order siblings by "ENAME"

Example of a javascript tree control based on a SQL Query.