select c.cod_mitem,b.rot_ord,b.Plan_wkhr_m,(sum(a.plan_wkhr_n) + sum(a.plan_wkhr_o))from web_wlms_o4sequence_user a  
        left join web_wlms_o3sequence b on a.rot_ord_id = b.id 
        left join web_wlms_o2order c on b.num_ord_id = c.id 
        group by c.cod_mitem,b.rot_ord,b.Plan_wkhr_m order by rot_ord