declare @table table
(
    id int ,
    name nvarchar(10),
    a varchar(10),
    superior_id int
)
insert @table
select 266, N'河北', 002, 1 union all
select 282, N'长沙', 001, 1 union all
select 503, N'石家庄', 345, 266

select * from @table t where exists(select * from @table where id= t.superior_id )
--#1.第一行记录superior_id=1, 当它从@table表中找id=1时, 没找到，所以第一行记录被过滤了
--#2.同上
--#3.第三行记录superior_id=266, 当它从@table表中找id=266时, 发现存在一条这样的记录，所以被返回。
/*
id    name    a    superior_id
503    石家庄    345    266
*/

------解决方案--------------------
沒看明白什麼意思，按你寫的語句，應只能輸出
503 石家庄 345 266 
這一倏記錄吧

------解决方案--------------------
SQL code
create table tb(id int, name nvarchar(64), a varchar(32),superior_id int)
insert tb 
select 266,'河北','002',1 union all 
select 282,'长沙','001',1  union all
select 503,'石家庄','345',266 


select * from tb where  id in (select superior_id from tb t where exists(select 1 from tb where id= t.superior_id ))
union 
select * from tb t where exists(select 1 from tb where id= t.superior_id )
/*
id    name    a    superior_id
266    河北    002    1
503    石家庄    345    266
*/
drop table tb

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


select * from tab t where exists(select * from tab where id= t.superior_id )

------解决方案--------------------
select * from @table t where exists(select 1 from @table where t.id = superior_id )

union all

select * from @table t where exists(select 1 from @table where id = t.superior_id )


------解决方案--------------------
用了CTE查询，方便点：
SQL code
create table tb(id int, name nvarchar(64), a varchar(32),superior_id int)
insert tb 
select 266,N'河北','002',1 union all 
select 282,N'长沙','001',1  union all
select 503,N'石家庄','345',266 union all
select 509,N'邯郸','645',503 


with t(id,name,superior_id,IsChild)
as
(
select id,name,superior_id,0 as IsChild from tb
where superior_id=1
union all
select tb.id,tb.name,tb.superior_id,t.IsChild+1 as IsChild from tb
join t on tb.superior_id=t.id
where tb.superior_id!=1
)

select * from tb
where (id in (select superior_id from t where isChild!=0) and superior_id=1)
 or (id in (select id from t where isChild!=0))