递归 CTE 以找到所有子级父级和深度的总数

问题描述

我希望像这样使用递归 CTE 为所有 childcount 和 parentcount 以及 path 和 level 以及 currentlevel 找到 Total

Id  ParentId    Name    Path        Level   CurrentLevel    ChildrenCount   ParentCount
1   NULL         a      1            4         1               3               0
3   1            c      3,1          3         2               2               1
4   3            d      4,3,1        2         3               1               2
5   4            f      5,4,1      1         4               0               3
2   NULL         b      2            5         1               5               0
6   2            g      6,2          4         2               4               1               
7   6            h      7,6,2        3         3               3               2
8   7            i      8,7.6.2      2         4               2               3
9   8            j      9,8,7,2    1         5               0               4
10  8            k      10,2   1         5               0               4

我尝试了下面的代码，但是我不知道如何获取childrencount和parentcount以及path和level和currentlevel，如何编码它动态计算它。

CREATE TABLE #temp([id] int,[parentid] int null,[name] varchar(5));

INSERT INTO #temp ([id],[parentid],[name])
VALUES   ('1',null,'a'),('2','b'),('3','1','c'),('4','3','d'),('5','4','e'),('6','2','f'),('7','6','h'),('8','7','i'),('9','8','j'),('10','k')
WITH AllChildrens as
(
    SELECT p.*,CAST(P.Id AS VarChar(Max)) as [Path]
    FROM Department P where p.ParentId is null

    UNION ALL

    SELECT P1.*,CAST(P1.Id AS VarChar(Max)) + ',' + M.[Path]
    FROM Department P1
    INNER JOIN AllChildrens M
    ON M.Id = P1.ParentId
)
SELECT Id,ParentId,Name,Path From AllChildrens order by Id 

解决方法

一种选择是使用数据类型 hierarchyid

示例

;with cteP as (
      Select ID,parentid,Name,HierID = convert(hierarchyid,concat('/',ID,'/'))
      From   #Temp 
      Where  parentid is null
      Union  All
      Select ID  = r.ID,parentid  = r.parentid,Name   = r.Name,concat(p.HierID.ToString(),r.ID,'/'))
      From   #Temp r
      Join   cteP p on r.parentid  = p.ID)
Select ID,Path      = HierID.ToString(),Depth     = ( Select max(HierID.GetLevel() ) from cteP where HierID.ToString() like A.HierID.ToString()+'%') - HierID.GetLevel(),Lvl       = HierID.GetLevel(),ChildCnt  = ( Select count(*) from cteP where HierID.ToString() like A.HierID.ToString()+'%') -1,ParentCnt = len(HierID.ToString()) - len(replace(HierID.ToString(),'/','')) - 2
 From cteP A
 Order By A.HierID

结果