create table G (goods varchar(2),lot varchar(3),bal int)
create table O (oid varchar,goods varchar(2),qty int)
insert G select 'aa','p01',5
   union select 'aa','p02',10
   union select 'bb','p01',20

insert O select '1','aa',11
   union select '1','bb',10
   union select '2','aa',2
   union select '3','aa',1

select oid,b.goods,lot,deli=(case when sq>sb then sb else sq end)-(case when sq-qty<sb-bal then sb-bal else sq-qty end)
from ( select *,sq=( select sum(qty) 
                             from o
                             where oid <=a.oid and goods=a.goods
                           )
       from o a
     ) b
     join
     ( select *,sb=( select sum(bal)
                              from g
                              where goods=a.goods and lot<=a.lot
                            )
       from g a
     ) c
     on b.goods=c.goods and sq-qty<sb and sq>sb-bal
order by oid,b.goods,lot

drop table g,o