这个语句运行效率低 请各位大神们帮忙改改

create or replace procedure wz.pr_t_342_purchase_insertdata(
          ls_purplan_id in varchar2,ls_year_mon in varchar2,ls_plan_type in varchar2)
is
  ls_orga_id varchar2(16);
  ls_orga_name varchar2(32);
  ls_re varchar2(128);  cursor cursor1 is
    select t3.material_id,t3.material_name,t3.specification,t3.measure_id,
                                      sum(t2.req_amount) as req_quantity,
                                      min(t2.need_day) as need_day,
                                      count(*) as dept_num,
                                      max(t2.req_amount) as max_req_amount
                                      from wz.t_wrequirment t1,wz.t_drequirment t2,wz.t_material t3 
                                      where t1.status='6' and to_char(t1.apply_day,'yyyymm')>='200710'
                                      and to_char(t1.apply_day,'yyyymm')<=ls_year_mon
                                      and t1.requir_type=ls_plan_type
                                      and t1.requir_id=t2.requir_id and t2.material_id=t3.material_id 
                                      and t2.purplan_id is null and t2.material_id is not null
                                      and t2.req_amount>0 AND T2.REQ_AMOUNT IS NOT NULL and nvl(t2.status,'0')<>'B'  
                                      group by t3.material_id,t3.material_name,t3.specification,t3.measure_id;
  cursor cursor2 is
      select t2.material_id,t2.re from wz.t_wrequirment t1,wz.t_drequirment t2
                                      where t1.status='6' and to_char(t1.apply_day,'yyyymm')>='200710'
                                      and to_char(t1.apply_day,'yyyymm')<=ls_year_mon
                                      and t1.requir_type=ls_plan_type
                                      and t1.requir_id=t2.requir_id
                                      and t2.purplan_id is null and t2.material_id is not null
                                      and t2.req_amount>0 AND T2.REQ_AMOUNT IS NOT NULL and nvl(t2.status,'0')<>'B'  
                                      and t2.re is not null;begin   for result1 in cursor1 loop
     
       select distinct max(t1.orga_id),max(t1.orga_name) into ls_orga_id,ls_orga_name
                                      from wz.t_wrequirment t1,wz.t_drequirment t2
                                      where t1.status='6' and to_char(t1.apply_day,'yyyymm')>='200710'
                                      and to_char(t1.apply_day,'yyyymm')<=ls_year_mon
                                      and t1.requir_type=ls_plan_type
                                      and t1.requir_id=t2.requir_id AND T2.REQ_AMOUNT IS NOT NULL and nvl(t2.status,'0')<>'B'  
                                      and t2.req_amount=result1.max_req_amount
                                      and t2.material_id=result1.material_id
                                      and t2.purplan_id is null;       ls_re:='';
       for result2 in cursor2 loop
         if result2.material_id=result1.material_id then
             ls_re:=ls_re || result2.re;
         end if;
       end loop;       insert into wz.t_cg_plan (group_id,plan_type,purplan_id,year_mon,material_id,material_name,
                                 specification,req_quantity,req_day,plan_quantity,re,dept_num,orga_id,orga_name,measure_id,status)
                                 values('lh',ls_plan_type,ls_purplan_id,ls_year_mon,
                                        result1.material_id,result1.material_name,result1.specification,
                                        result1.req_quantity,result1.need_day,result1.req_quantity,ls_re,result1.dept_num,
                                        ls_orga_id,ls_orga_name,result1.measure_id,'00');   end loop;      update wz.t_drequirment
      set purchase_status='00',status='9',purplan_id=ls_purplan_id
      where requir_id in (select requir_id from wz.t_wrequirment
                          where status='6' and to_char(apply_day,'yyyymm')>='200710'
                          and to_char(apply_day,'yyyymm')<=ls_year_mon
                          and requir_type=ls_plan_type)
      and purplan_id is null and nvl(status,'0')<>'B'  ;   commit;   exception
     when others then
     raise;end pr_t_342_purchase_insertdata;