求SQL语句，取某物料的下层所有物料

将黄色背景的数据取出来。

谢谢！
[解决办法]

[解决办法]
CREATE TABLE test([阶层] int,[序号] varchar(50),[标志] varchar(2))
go
insert into test
select 1,'0010','' union all
select 2,'0010010','' union all
select 3,'0010010010','' union all
select 2,'00100020','Y' union all
select 3,'001000200010','' union all
select 4,'0010002000100010','' union all
select 5,'00100020001000100010','' union all
select 2,'00100030','' union all
select 3,'001000300010','' union all
select 4,'0010003000100010','Y' union all
select 5,'00100030001000100010',''

SELECT * FROM test as a,(SELECT [序号] FROM test WHERE [标志]='Y') as b
WHERE a.[序号] LIKE b.[序号]+'%' and a.[标志]<>'Y'

drop table test