从SQL 2005中的自引用表获取层次结构数据

Question

我正在使用 SQL 2005，现有数百万条记录的数据（因此数据结构无法更改），我正在尝试执行以下操作：

我有一些数据（以下示例来自另一个问题并进行了一些修改以显示什么我试图在自引用表中实现）。我需要按以下格式提取结果树：

Parent
 Child1 of Parent
  Child1 of Child 1
  Child2 of Child 1
 Child2 of Parent
  Child1 of Child 2

我的实际数据深度为 9 层 - 我尝试使用 CTE 获取结果。然而，这会产生以下结果：

Parent
 Child1 of Parent
 Child2 of Parent
  Child1 of Child 1
  Child2 of Child 1
  Child1 of Child 2

这是我正在使用的查询类型的示例：

create table workshop (
w_id smallint primary key,
p_id smallint,
s_date smalldatetime,
title varchar(100))
go

alter table workshop add constraint fk_wkshp foreign key (p_id)
references workshop(w_id)
go

insert into workshop (w_id, p_id, s_date, title) values (1, null,
'5/2/2007', 'Parent')
insert into workshop (w_id, p_id, s_date, title) values (2, 1,
'5/3/2007', 'Child 1 of the parent')
insert into workshop (w_id, p_id, s_date, title) values (3, 1,
'5/5/2007', 'Child 2 of the parent')
insert into workshop (w_id, p_id, s_date, title) values (4, 2,
'5/4/2007', 'Child of Child 1')
insert into workshop (w_id, p_id, s_date, title) values (5, 2,
'5/5/2007', 'Child 2 of the child of the parent')
insert into workshop (w_id, p_id, s_date, title) values (6, 3,
'5/7/2007', 'Child of the child 2')
insert into workshop (w_id, p_id, s_date, title) values (7, null,
'5/7/2007', '2nd Parent')
insert into workshop (w_id, p_id, s_date, title) values (8, 7,
'5/7/2007', 'Child of 2nd Parent')
insert into workshop (w_id, p_id, s_date, title) values (9, 7,
'5/7/2007', 'Child of 2nd Parent')
go

declare @id smallint
set @id = 1

;with events (w_id, p_id, s_date, title)
as
(
-- the anchor member
select
w_id, p_id, s_date, title
from
workshop
where w_id = @id

-- the recursive member
union all

select
w.w_id, w.p_id, w.s_date, w.title
from
workshop w
-- the key is to join to the CTE
join events e on e.w_id = w.p_id
)

select * from events

drop table workshop
go

我已经看到了与此相关的各种其他问题，但看不到我的问题的答案。最近的事情是 oracle“先验连接”，如果我使用 oracle dB，那就太好了！有什么想法吗？

干杯， 贾森

Answer 1

我想我已经找到了答案，那就是我加入的是主播成员而不是研讨会桌上。感谢 gjvdkamp 这篇类似的文章，它让我重新评估了错误的“真实”sql 语句。