Tsql 递归CTE顺序

我很难弄清楚如何使用递归CTE对结果进行递归排序。我的意思是，这是一个简化的数据集：

我将此作为输入：

declare @sections table (id int, parent int);

insert into @sections values (1, 1);
insert into @sections values (2, 2);
insert into @sections values (3, 2);
insert into @sections values (4, 2);
insert into @sections values (5, 4);
insert into @sections values (6, 1);
insert into @sections values (7, 6);
insert into @sections values (8, 6);
insert into @sections values (9, 6);
insert into @sections values (10, 9);

-- hierarchical view
--1
--  6
--      7
--      8
--          10
--      9
--2
--  3
--  4
--      5

我想要这个作为输出 编辑：行的顺序是这里的重要部分

这是我能做的最好的：

with section_cte as
(
    select id, parent, 0 'depth' from @sections where id = parent
    union all
    select cte.id, cte.parent, depth + 1 
    from @sections s join section_cte cte on s.parent = cte.id where s.id <> s.parent
)
select *from section_cte

谁能帮我调整一下这个查询以得到我需要的

---

谢谢

您错过了需要从cte识别深度的部分

WITH CTE AS (
SELECT
    id
    , parent
    , 0 AS depth
FROM
    @sections
WHERE
    id=parent

UNION ALL

SELECT
    s.id
    , s.parent
    , c.depth + 1
FROM
    @sections s
    JOIN CTE c ON s.parent=c.id AND s.id <> s.parent
)
SELECT *
FROM CTE;

---

在递归构建期间，添加序列是一件小事。在下面的示例中，顺序由标题的字母顺序决定，但您可以使用任何其他可用的键/序列

Declare @Table table (ID int,Pt int,Title varchar(50))
Insert into @Table values (0,null,'Tags'),(1,0,'Transportation'),(2,1,'Boats'),(3,1,'Cars'),(4,1,'Planes'),(5,1,'Trains'),(6,0,'Technology'),(7,6,'FTP'),(8,6,'HTTP'),(9,0,'Finance'),(10,9,'FTP'),(11,9,'401K'),(12,2,'Sail'),(13,2,'Powered'),(14,6,'Internet'),(15,6,'Database'),(16,15,'SQL Server'),(17,15,'MySQL'),(18,15,'MS Access')

Declare @Top  int = null          --<<  Sets top of Hier Try 9
Declare @Nest varchar(25) ='   '  --<<  Optional: Added for readability

;with cteHB (Seq,ID,Pt,Lvl,Title) as (
    Select  Seq  = cast(1000+Row_Number() over (Order by Title) as varchar(500))
           ,ID
           ,Pt
           ,Lvl=1
           ,Title 
     From   @Table 
     Where  IsNull(@Top,-1) = case when @Top is null then isnull(Pt,-1) else ID end
     Union  All
     Select Seq  = cast(concat(cteHB.Seq,'.',1000+Row_Number() over (Order by cteCD.Title)) as varchar(500))
           ,cteCD.ID
           ,cteCD.Pt,cteHB.Lvl+1
           ,cteCD.Title 
     From   @Table cteCD 
     Join   cteHB on cteCD.Pt = cteHB.ID)
     ,cteR1 as (Select Seq,ID,R1=Row_Number() over (Order By Seq) From cteHB)
     ,cteR2 as (Select A.Seq,A.ID,R2=Max(B.R1) From cteR1 A Join cteR1 B on (B.Seq like A.Seq+'%') Group By A.Seq,A.ID )
Select Hier='HierName'
      ,B.R1  
      ,C.R2
      ,A.ID
      ,A.Pt
      ,A.Lvl
      ,Title = Replicate(@Nest,A.Lvl) + A.Title
      --,A.Seq               --<< Normally Excluded, but you can see how the sequence is built
 From cteHB A
 Join cteR1 B on A.ID=B.ID
 Join cteR2 C on A.ID=C.ID
 Order By A.Seq              --<< Use R1 if Range Keys are used

现在，您可能已经注意到R1和R2。这些是我的范围键，通常用于聚合数据而无需递归。如果不需要或不需要这些，只需在最终选择中删除字符1和字符2以及相应的引用

编辑

---

您还可以选择层次结构的一部分，即技术及其子级

您需要的技巧是创建一个与您的业务规则匹配的排序字符串。像这样的

WITH CTE AS (
SELECT
    id, parent, 0 AS depth
    --For MS SQL Server 2012+
    ,cast(format(id,'0000') as varchar(max)) sort
    --For previous versions
    ,cast(stuff('0000',5-len(cast(id as varchar)),len(cast(id as varchar)),id) as varchar(max)) sort1
FROM @sections
WHERE id=parent
UNION ALL
SELECT s.id, s.parent, c.depth + 1
    ,sort + cast(format(s.id,'0000') as varchar(max)) sort
    ,sort + cast(stuff('0000',5-len(cast(s.id as varchar)),len(cast(s.id as varchar)),s.id) as varchar(max)) sort1
FROM @sections s
    inner join CTE c ON s.parent=c.id AND s.id <> s.parent
)
SELECT *
FROM CTE
order by sort --or by sort1 depending on version

---

你能解释一下为什么你选择了根级别的项目是它们自己的父母的方案吗？在我们的系统中，根级别通常是id=parent。这就是为什么模拟数据是这样的way@TheGameiswar输出中的行顺序就好像是先递归地遍历树一样。谢谢，这很有帮助，但它并没有给出我想要的结果。这将按节id 1、2、3、…、10的顺序返回节。我期望的顺序是TSQL中的1 6 7 8 10 9 2 3 4 5，保证输出数据集顺序的唯一方法是使用order by子句。在这种情况下，根据你所说的，我不知道如何制作。光标在ID上循环，但这变成了一个完全不同的问题。我接受这个答案，因为这是我的数据，但约翰·卡佩莱蒂的答案也很有帮助

Hier        R1  R2  ID  Pt      Lvl    Title
HierName    1   19  0   NULL    1      Tags
HierName    2   4   9   0       2         Finance
HierName    3   3   11  9       3            401K
HierName    4   4   10  9       3            FTP
HierName    5   12  6   0       2         Technology
HierName    6   9   15  6       3            Database
HierName    7   7   18  15      4               MS Access
HierName    8   8   17  15      4               MySQL
HierName    9   9   16  15      4               SQL Server
HierName    10  10  7   6       3            FTP
HierName    11  11  8   6       3            HTTP
HierName    12  12  14  6       3            Internet
HierName    13  19  1   0       2         Transportation
HierName    14  16  2   1       3            Boats
HierName    15  15  13  2       4               Powered
HierName    16  16  12  2       4               Sail
HierName    17  17  3   1       3            Cars
HierName    18  18  4   1       3            Planes
HierName    19  19  5   1       3            Trains

WITH CTE AS (
SELECT
    id, parent, 0 AS depth
    --For MS SQL Server 2012+
    ,cast(format(id,'0000') as varchar(max)) sort
    --For previous versions
    ,cast(stuff('0000',5-len(cast(id as varchar)),len(cast(id as varchar)),id) as varchar(max)) sort1
FROM @sections
WHERE id=parent
UNION ALL
SELECT s.id, s.parent, c.depth + 1
    ,sort + cast(format(s.id,'0000') as varchar(max)) sort
    ,sort + cast(stuff('0000',5-len(cast(s.id as varchar)),len(cast(s.id as varchar)),s.id) as varchar(max)) sort1
FROM @sections s
    inner join CTE c ON s.parent=c.id AND s.id <> s.parent
)
SELECT *
FROM CTE
order by sort --or by sort1 depending on version