判断下面是否有子节点的 sql

---------------------------------  判断下面是否有子节点的 sql
select a.*, nvl(b.count, 0) as CHILDNUM
  from (--根据父节点查当前局向
        select *
          from baf_pub_bureau a
         where a.parentbureauid = '0000017'
           and a.isvalid = 'Y') a,
           --下面是查当前局向有多少个下级节点
       (select b.parentbureauid, count(1) as count
          from (select *
                  from baf_pub_bureau a
                 where a.parentbureauid = '0000017') a,
               baf_pub_bureau b
         where a.bureauid = b.parentbureauid
           AND b.isvalid = 'Y'
         group by b.parentbureauid) b
where a.bureauid = b.parentbureauid(+)
大家看下这个SQL,
不要在页面循环判断有无子节点了