How to write a SQL statement to return all children of each root,extend to each root - sql

Question

I have a table.
the value of [contents] can insert any word(Below are just examples)
create table #TreeTable (
Id uniqueidentifier,
Contents NVARCHAR(200),
ParentId uniqueidentifier,
Floors Int,
Sort Int,
)
insert into #TreeTable([Id], [ParentId], [Contents],[Floors],[Sort]) values
(1, 0, '1',1,1),
(2, 0, '2',1,2),
(3, 1, '1-1',2,1),
(4, 1, '1-2',2,2),
(5, 2, '2-1',2,1),
(6, 3, '1-1-1',3,1),
(7, 4, '1-2-1',3,1);
(8, 4, '1-2-2',3,2),
(9, 6, '1-1-1-1',4,1),
(10, 6,'1-1-1-2',4,2);
I want to write a T-SQL statement that will return all children of each root with the root ID　and Below is the result I expected
[Id][ParentId][Contents] [Levels][Sort]
(1, 0, '1', 1, 1)
(3, 1, '1-1', 2, 1)
(6, 3, '1-1-1', 3, 1)
(9, 6, '1-1-1-1', 4, 1)
(10, 6, '1-1-1-2', 4, 2)
(4, 1, '1-2', 2, 2)
(7, 4, '1-2-1', 3, 1)
(8, 4, '1-2-2', 3, 2)
(2, 0, '2', 1, 2)
(5, 2, '2-1', 2, 1)
The depth of the tree may be arbitrarily long
I try to use this ，but the reuslt is not what i expected
with RecursiveTable as(
------ start-------
SELECT a.*
FROM TreeTable a
WHERE
a.ParentId = 0
------ end ---------
union all
SELECT b.*
FROM TreeTable b
join RecursiveTable a on a.Id =b.ParentId
)
select * from RecursiveTable

Answer 1

If we may believe [Contents] values, then simply
SELECT [Id],
[ParentId],
[Contents],
LEN([Contents]) - LEN(REPLACE([Contents], '-', '')) + 1 [Levels],
[Sort]
FROM #TreeTable
ORDER BY [Contents];
fiddle
If not then
WITH cte AS
(
SELECT [Id], [ParentId], CAST([Sort] AS NCHAR), [Sort], 1 [Levels]
FROM #TreeTable
WHERE [ParentId] = 0
UNION ALL
SELECT t.[Id], t.[ParentId], cte.[Contents] + '-' + t.[Sort], t.[Sort], 1 + cte.[Levels]
FROM #TreeTable t
JOIN cte ON t.[ParentId] = cte.[Id]
)
SELECT [Id], [ParentId], [Contents], [Levels], [Sort]
FROM cte
ORDER BY [Contents];
fiddle (optimize types adjusting for their matching in CTE by yourself).

Answer 2

U can try:
WITH RECURSIVETABLE (ID, [PARENTID], [CONTENTS],[LEVELS],[SORT],[ORDER]) AS
(
------ START-------
SELECT A.ID, A.[PARENTID], A.[CONTENTS],A.[FLOORS],A.[SORT], CONVERT(VARCHAR(250),RIGHT('00000'+CONVERT(VARCHAR(50),ROW_NUMBER() OVER(ORDER BY SORT)),5))
FROM #TREETABLE A
WHERE
A.PARENTID = 0
------ END ---------
UNION ALL
SELECT B.ID, B.[PARENTID], B.[CONTENTS],B.[FLOORS],B.[SORT], CONVERT(VARCHAR(250),CONVERT(VARCHAR,A.[ORDER])+'.'+RIGHT('00000'+CONVERT(VARCHAR(50),ROW_NUMBER() OVER(ORDER BY B.[FLOORS],B.SORT)),5))
FROM #TREETABLE B
JOIN RECURSIVETABLE A ON A.ID =B.PARENTID
)
SELECT * FROM RECURSIVETABLE ORDER BY [ORDER]