SELECT pp.*,
(select user.name
from dlp_base.sys_user user
where user.user_id = pp.primary_auditor_id) as primary_auditor_name
, (
select user.name
from dlp_base.sys_user user
where user.user_id = pp.approver_id) as approver_name
, (
select user.name
from dlp_base.sys_user user
where user.user_id = pp.create_id) as create_name
FROM purchasing_plan pp