Question

我必须进行更新。我真的卡住了。这是一个经典的分层员工表问题，但有一个转折点。请看这个用户树： employees

（完全与我的问题无关，只是我在google图片中找到的内容）

让我们假设以下Id：

RM1: EmpId 1, ParentId null

AM1: EmpId 2, ParentId 1

MGR1: EmpId 3, ParentId 2

MGR2: EmpId 4, ParentId 2

EMP1: EmpId 5, ParentId 3

EMP2: EmpId 6, ParentId 3

EMP3: EmpId 7, ParentId 4

EMP4: EmpId 8, ParentId 4

我需要添加另一列，我们称之为parentSpecialId。此id是root（AM1和AM2）下面的用户的id。 AM1和AM2以下的所有用户都应将parentSpecialId设置为root用户以下的用户。

这给了我们：

RM1: EmpId 1, ParentId null parentSpecialId null

AM1: EmpId 2, ParentId 1    parentSpecialId null

MGR1: EmpId 3, ParentId 2   parentSpecialId 2

MGR2: EmpId 4, ParentId 2   parentSpecialId 2

EMP1: EmpId 5, ParentId 3   parentSpecialId 2

EMP2: EmpId 6, ParentId 3   parentSpecialId 2

EMP3: EmpId 7, ParentId 4   parentSpecialId 2

EMP4: EmpId 8, ParentId 4   parentSpecialId 2

我所拥有的只是这个CTE，它为我提供了AM1和AM2的结果集。因此，我需要一直遍历到EMPX并使用Id 2更新parentSpecialId AM1和AM2的所有用户相同。当然，它需要通过动态，在现实生活中我有12个这样的用户在root下面。

有意义吗？

这是我的CTE：

    WITH EmpsCTE AS
(
    SELECT id, parent, name, 0 AS EmployeeLevel
    FROM Employee
    WHERE parent = 0 
    UNION ALL
    SELECT e.id, e.parent, e.name, EmployeeLevel + 1
    FROM EmpsCTE AS p 
    JOIN Employee AS e ON e.parent = p.id 
)
SELECT id, parent, name, EmployeeLevel
From EmpsCTE where EmployeeLevel = 1

哦，我使用的是Sql server 2008 R2

Answer 1

示例数据：

declare @T table
(
  Name varchar(10),
  EmpId int,
  ParentId int,
  ParentSpecialID int
);

insert into @T(Name, EmpId, ParentId) values
('RM1',  1, null),
('AM1',  2, 1),
('MGR1', 3, 2),
('MGR2', 4, 2),
('EMP1', 5, 3),
('EMP2', 6, 3),
('EMP3', 7, 4),
('EMP4', 8, 4);

更新声明：

with C as
(
  select T3.EmpId,
         T2.EmpId as ParentSpecialId
  from @T as T1
    inner join @T as T2
      on T1.EmpId = T2.ParentId
    inner join @T as T3
      on T2.EmpId = T3.ParentId  
  where T1.ParentId is null
  union all
  select T.EmpId,
         C.ParentSpecialId
  from @T as T
    inner join C
      on T.ParentId = C.EmpId       
)
update T
set ParentSpecialId = C.ParentSpecialId
from @T as T
  inner join C
    on T.EmpId = C.EmpId

Answer 2

处理任意深度的树：

declare @T table ( Name varchar(16), EmpId int, ParentId int ); 

insert into @T(Name, EmpId, ParentId) values 
  ('RM1',  1, null),
  ('AM1',  2, 1), 
  ('MGR1', 3, 2), 
  ('MGR2', 4, 2), 
  ('EMP1', 5, 3), 
  ('EMP2', 6, 3), 
  ('EMP3', 7, 4), 
  ('EMP4', 8, 4),
  ('AM2', 9, 1),
  ('MGR3', 10, 9),
  ('EMP5', 11, 10),
  ('Brown Noser', 12, 11),
  ('Intern', 13, 12),
  ('Coop', 14, 13),
  ('Nephew', 15, 14),
  ('Contractor', 16, 15);

; with CTE as (
  -- Start with the root(s).
  select Name, EmpId, ParentId, 0 as Depth, Cast(NULL as Int) as parentSpecialId
    from @T
    where ParentId is NULL
  union all
  -- Add the direct reports one layer at a time.
  select T.Name, T.EmpId, T.ParentId, CTE.Depth + 1, case when CTE.Depth = 1 then T.ParentId else CTE.parentSpecialId end
    from CTE inner join
      @T as T on T.ParentId = CTE.EmpID
    where T.ParentId = CTE.EmpId
  )
select *,
  ( select Name from CTE as R where R.EmpId = CTE.ParentId ) as ReportsTo,
  ( select Name from CTE as SC where SC.EmpId = CTE.parentSpecialId ) as SubCommander
  from CTE
  order by Depth, Name

感谢Mikael Eriksson设置样本数据！

更新分层员工表中的特殊ID

2 个答案: