select *
from tb
where fatherid in (
    select fatherid
    from tb
    group by fatherid
    having count(*) > 1
)

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

--存在主键字段，假设为Id

select *
from tb t
where exists (select 1 from tb where fatherid=t.fatherid and id<>t.id)