select * from a,b
where a.id=b.id(+) and instr(a1,b1)>0

------解决方案--------------------
SQL code

select a.*
  from a left join b
    on a.a1 = b.b1
 where b1 is not null;

------解决方案--------------------
SQL code
select * from a,b
where  a1 not in (select b1 from b where a.id=b.id(+))

------解决方案--------------------
select a.*  from a left join b on a.a2 = b.b2 and a.a1<>b.b1