select sum(t1.Sum) as rezult from table1 t1 INNER JOIN tabl2 t2;
ON t1.NBin1 == t2.NBin2;
where t2.Corp ==0;
into table table3

variant 1:
select sum(t1.Sum) as rezult from table1 t1, tabl2 t2;
where t1.NBin1 not in ;
(select NBin2 from table2 where Corp<>1)

variant 2:

select sum(t1.Sum) as rezult from table1 t1 INNER JOIN tabl2 t2;
ON t1.NBin1 != t2.NBin2 ;
where t2.Corp =1

Не отлаживал, не проверял, но в этом духе.