Join within same table to retrieve hierarchy (Parent-Child Hierarchy) - sql

Question

I have two tables - Master and Child. Child table contains hierarchal data for MainId stored in Master table.
Master.Name is Unique
Master.MainId = Child.ChildId
Child.ParentId = Child.ChildId
I have to retrieve all data from Child table for Master.RelDate and Master.Name. I thought it was a straight forward query but somehow not able to pull desired output. I'm ending up with just one Child table record no matter how I write query.
Is it to do with table structure or my query?
Note: None of the ParentIds and ChildIds are in sequence. That data comes from another system, I just put those values for simplicity.
IF OBJECT_ID('tempdb..#Master') IS NOT NULL BEGIN DROP TABLE #Master END
GO
IF OBJECT_ID('tempdb..#Child') IS NOT NULL BEGIN DROP TABLE #Child END
GO
CREATE TABLE #Master
(
Id BIGINT IDENTITY(1,1),
RelDate DATE NOT NULL,
MainId BIGINT NOT NULL,
Name VARCHAR(512) NOT NULL
)
GO
CREATE TABLE #Child
(
Id BIGINT IDENTITY(1,1),
RelDate DATE NOT NULL,
ChildId BIGINT NOT NULL,
ParentId BIGINT NULL,
Label VARCHAR(20) NULL,
Value VARCHAR(1024) NULL
)
GO
INSERT INTO #Master(RelDate,MainId,Name) VALUES ('2019-01-01',1,'Name1')
INSERT INTO #Master(RelDate,MainId,Name) VALUES ('2019-01-01',11,'Name11')
GO
INSERT INTO #Child(RelDate,ChildId,ParentId,Label,Value) VALUES
('2019-01-01',1,2,'Level10',NULL)
,('2019-01-01',2,3,'Level09',NULL)
,('2019-01-01',3,4,'Level08',NULL)
,('2019-01-01',4,5,'Level07',NULL)
,('2019-01-01',5,6,'Level06','This is level 6')
,('2019-01-01',6,7,'Level05',NULL)
,('2019-01-01',7,8,'Level04',NULL)
,('2019-01-01',8,9,'Level03','This is level 3')
,('2019-01-01',9,10,'Level02',NULL)
,('2019-01-01',10,11,'Level01',NULL) -- Always same
,('2019-01-01',11,NULL,'Root',NULL) -- Always same
INSERT INTO #Child(RelDate,ChildId,ParentId,Label,Value) VALUES
('2019-01-01',11,12,'Level10',NULL)
,('2019-01-01',12,13,'Level09',NULL)
,('2019-01-01',13,14,'Level08',NULL)
,('2019-01-01',14,15,'Level07',NULL)
,('2019-01-01',15,16,'Level06','This is level 6')
,('2019-01-01',16,17,'Level05',NULL)
,('2019-01-01',17,18,'Level04',NULL)
,('2019-01-01',18,19,'Level03','This is level 3')
,('2019-01-01',19,10,'Level02',NULL)
,('2019-01-01',10,11,'Level01',NULL) -- Always same
,('2019-01-01',11,NULL,'Root',NULL) -- Always same
GO
SELECT * FROM #Master
SELECT * FROM #Child
Desired output for RelDate = 2019-01-01 and Name = Name1
SELECT chld.*
FROM #Master mst (NOLOCK)
INNER JOIN #Child chld (NOLOCK) ON (mst.MainId = chld.ChildId)
LEFT JOIN #Child chld1 (NOLOCK) ON (chld.ParentId = chld.ChildId)
WHERE mst.RelDate = '2019-01-01' -- Input 1
AND mst.Name = 'Name1' -- Input 2
All the data from Child table
Id RelDate ChildId ParentId Label Value
1 2019-01-01 1 2 Level10 NULL
2 2019-01-01 2 3 Level09 NULL
3 2019-01-01 3 4 Level08 NULL
4 2019-01-01 4 5 Level07 NULL
5 2019-01-01 5 6 Level06 This is level 6
6 2019-01-01 6 7 Level05 NULL
7 2019-01-01 7 8 Level04 NULL
8 2019-01-01 8 9 Level03 This is level 3
9 2019-01-01 9 10 Level02 NULL
10 2019-01-01 10 11 Level01 NULL
11 2019-01-01 11 NULL Root NULL
Thanks in advance

Answer 1

select c.* from #Child c inner join #Master M
on M.MainId = C.ChildId
Id RelDate ChildId ParentId Label Value
1 2019-01-01 1 2 Level10 NULL
11 2019-01-01 11 NULL Root NULL
If this isn't the desired output, please provide your desired output.

Answer 2

It seams that data in the tables is kinda non logical. Especially with the 'Name11'. I assume that with every new rows you will lose one id from Childid column .Now we lose 'lvl2' at row 19.
I tried to figure out some solution, now my position here.
It works for 'Name1', but result for 'Name11' a bit different.
SELECT t2.*
FROM #Master mst
join #Child t1 ON mst.MainId = t1.ChildId
join #Child t2 ON t2.parentid >= t1.ChildId
WHERE mst.RelDate = '2019-01-01' -- Input 1
AND mst.Name = 'Name1' -- Input 2
order by t2.id
offset 0 rows
fetch first 10 rows only
Maybe it helps you a little. I will try to find a tricky solution.