Sql server 查询分层数据并获取链上的所有关系

我的父/子层次结构数据如下所示：

AgencyId  ParentAgencyId
6220        NULL
6221        6220
6222        6221
6223        6221
6224        6223
6219        6220
6225        NULL

我试图通过查询爬网层次结构来匹配所有关系，并设置一个类似于下面的级别

Parent    Child     Level
6220        6220        0
6220        6221        1
6220        6222        2
6220        6223        2
6220        6224        3
6220        6219        1
6221        6222        1
6221        6223        1
6221        6224        2
6223        6224        1
6225        6225        0

如果该机构没有母公司，则其级别为零

我试图做到这一点的代码是：

DECLARE @AgencyCount INT
DECLARE @i INT = 1
DECLARE @AgencyId INT

IF OBJECT_ID('tempdb..#tmpAgencies') > 0
DROP TABLE #tmpAgencies

CREATE TABLE #tmpAgencies (ID INT IDENTITY(1,1), AgencyId INT)
INSERT INTO #tmpAgencies SELECT AgencyId FROM dbo.Agency WHERE CreatorId = 59641 

IF OBJECT_ID('tempdb..#ChildAgencies') > 0
DROP TABLE #ChildAgencies

CREATE TABLE #ChildAgencies(AgencyId INT, ParentAgencyId INT, IsMultiAgencyOffice BIT,     LevelCount INT)  

SELECT @AgencyCount = COUNT(AgencyId) FROM #tmpAgencies         

WHILE @i < @AgencyCount

BEGIN  

    DECLARE @InsertedCount INT
    DECLARE @AgencyLevel INT = 0

    SELECT @AgencyId = AgencyId FROM #tmpAgencies AS TA WHERE ID = @i

    INSERT INTO #ChildAgencies(AgencyId, ParentAgencyId, IsMultiAgencyOffice, LevelCount)
    SELECT AgencyId, @AgencyId, IsMultiAgencyOffice, @AgencyLevel   
    FROM dbo.Agency
    WHERE AgencyId = @AgencyId

    SET @InsertedCount = @@ROWCOUNT

    WHILE @InsertedCount > 0
        BEGIN  

            SET @InsertedCount = NULL
            SET @AgencyLevel = @AgencyLevel + 1      

            INSERT INTO #ChildAgencies(AgencyId, ParentAgencyId, IsMultiAgencyOffice, LevelCount)
            SELECT AgencyId, @AgencyId, IsMultiAgencyOffice, @AgencyLevel
            FROM dbo.Agency AG
            WHERE AgencyId NOT IN (SELECT AgencyId FROM #ChildAgencies)
                AND ParentAgencyId IN (SELECT AgencyId FROM #ChildAgencies)
                AND StatusCode <> 109 /*QA-Deleted*/

            SET @InsertedCount = @@ROWCOUNT


        END  



    SET @i = @i + 1

END

我借用了其他东西的最里面的循环，它几乎完成了我想要的。我知道循环是不受欢迎的。我最初试图用递归CTE来实现这一点，但无法让它工作。另外，我真的很讨厌where子句中的子查询，但是一旦我开始得到我想要的结果，我就要解决这个问题

---

谢谢

我只需要一个简单的循环就可以了

-- load some data into some table 


drop table tbl; 

create table tbl(id int, parentid int, level int);

insert into tbl(id, parentid) values (1, 2);
insert into tbl(id, parentid) values (2, NULL);
insert into tbl(id, parentid) values (3, 1);
insert into tbl(id, parentid) values (4, NULL);
insert into tbl(id, parentid) values (5, NULL);
insert into tbl(id, parentid) values (6, 5);


-- update the levels 

declare @done int;  
declare @lvl int;

set @done = 0;
set @lvl = 0;

update tbl set [level] = 0 where parentid is null;

set @lvl = 0;

while (@done = 0) 

BEGIN

  update t2 
  set t2.[level] = t1.[level] + 1
  from tbl t2 join tbl t1 on t1.[level] = @lvl and t2.parentid = t1.id;

  set @lvl = @lvl + 1;

  if (not (exists (select null from tbl where [level] is null)))
  begin
     set @done = 1
  end

END; 




select * From tbl ;

---

在这种情况下，通常需要：

Parent    Child     Level
6220        6220        0
6220        6221        1
6220        6222        2
6220        6223        2
6220        6224        3
6220        6219        1
6225        6225        0

而不是：

6221        6222        1
6221        6223        1
6221        6224        2
6223        6224        1

您可以使用递归CTE获得第一部分：

with cte as (
      select AgencyId as Parent, AgencyId as Child, 0 as level
      from Agency
      where ParentAgencyId is null
      union all
      select cte.Parent, a.AgencyId, cte.level + 1
      from cte join
           Agency a
           on a.ParentAgencyId = cte.Child
   )
select *
from cte;

是一个SQL小提琴，显示了它的作用

此版本似乎产生了您想要的输出：

with cte as (
      select AgencyId as Parent, AgencyId as Child, 0 as level
      from Agency
      where ParentAgencyId is null
      union all
      select cte.Parent, a.AgencyId, cte.level + 1
      from cte join
           Agency a
           on a.ParentAgencyId = cte.Child
      union all
      select a.ParentAgencyId, a.AgencyId, cte.level + 1
      from cte join
           Agency a
           on a.ParentAgencyId = cte.Child
   )
select distinct *
from cte;

SQL小提琴是。我从未使用过带有两个union all子句的递归CTE

编辑：

此版本生成所需的输出。我似乎已经将上述问题过度复杂化了，但在此过程中，我确实了解到递归CTE可以有两个union all子查询：

 cte as (
  select AgencyId as Parent, AgencyId as Child, 0 as level, ParentAgencyId as OriginalPA
  from Agency
  union all
  select cte.Parent, a.AgencyId, cte.level + 1, OriginalPA
  from cte join
       Agency a
       on a.ParentAgencyId = cte.Child
)
select Parent, Child, Level
from cte
where level >  0 or OriginalPA is null;

---

你可以看到它在工作。

所以，这正是我想要的。我是从这样开始的，减去一个工会。我现在正在玩它，但它似乎起了作用。谢谢我错了，这不会产生预期的结果。它提供了6220 6219 16220 6220 0 6220 6221 16220 6222 6220 6223 2 6220 6224 3 6221 6222 2 6221 6223 2 6221 6224 3 6223 3 6225 6225 0