PA Work Breakdown Structure

SELECT
        p.project_number,
        p.project_name,
        substr(p.organization_name,1,60) project_organization, 
        p.project_status,
        p.start_date,
        p.completion_date,
        p.project_id project_id_1,
        t.task_id task_id_1
FROM
        pa_tasks t,
        pa_proj_info_view p
WHERE	decode(:top_task_id,'',t.parent_task_id,'All',t.parent_task_id,null)  
             is null
and     decode(:top_task_id,'',t.task_id,'All',t.task_id,:top_task_id) = t.task_id
and     t.project_id = p.project_id
and     p.project_id = :proj
order by p.project_name, t.task_number