select lt.*,lh.*,lo.*,ls.* from lab_head lh
left outer join lab_order lo on lo.lab_order_number=lh.lab_order_number
left outer join lab_items lt on lt.lab_items_code=lo.lab_items_code
left outer join lab_items_sub_group ls on ls.lab_items_sub_group_code=lo.lab_items_sub_group_code
where lh.vn="550725074724" and lo.confirm="Y" order by ls.lab_items_sub_group_code,lt.display_order
ควรเพิ่มอะไรตรงไหนบ้างครับ