How to create SQL Server tree in one row? - sql

Question

create table Test
(
Id int identity,
Name varchar(50) not null,
SName varchar(50) null,
ParentId int null
)
insert into Test
values ('aaa', 'bbb', null), ('adf', '22b', null), ('aad', 'bbsd',2),('asdsaa', 'bf', 3),('sdfs','sdf',3),('iopio','uiopio',3)
select * from Test
I have a table with parentid, and I want to get something like that
Name SName "aaa" "bbb" , "adf" {"aad":{"asdsaa":"bf"}}
from the selected values
I have been trying to get it with a recursive query, but...
WITH tree_view AS
(
SELECT
Id, ParentId, Name, SName
FROM
Test
UNION ALL
SELECT
parent.Id, parent.ParentId, parent.Name, parent.SName
FROM
Test parent
JOIN
tree_view tv ON parent.ParentId = tv.Id
)
SELECT DISTINCT *
FROM tree_view
I want to get this
if the parent id is not null, in one sell I want to get Name:SName in Sname field

Answer 1

I think you need to use PIVOT:
Below is similar solution which you can try
Sample Table creation:
CREATE TABLE [dbo].[TestTable](
[Id] [int] NULL,
[Name] [nvarchar](50) NULL,
[Description] [nvarchar](50) NULL)
Inserting sample values:
INSERT INTO TestTable VALUES (1,'Test1a','TestDesc1a')
INSERT INTO TestTable VALUES (2,'Test1b','TestDesc1b')
INSERT INTO TestTable VALUES (3,'Test2a','TestDesc2a')
INSERT INTO TestTable VALUES (4,'Test2b','TestDesc2b')
Query to get the desired output using Pivot:
SELECT 'Name' AS [Column], [1], [2],[3],[4]
FROM
(SELECT Name, id from TestTable) AS ST
PIVOT
(Max(Name) FOR ID IN ([1], [2],[3],[4])) AS PT
UNION
SELECT 'Description' AS [Column], [1], [2],[3],[4]
FROM
(SELECT id,[Description] from TestTable) AS ST
PIVOT
(Max([Description]) FOR ID IN ([1], [2],[3],[4])) AS PT
ORDER BY [Column] DESC
OutPut:
Column 1 2 3 4
Name Test1a Test1b Test2a Test2b
Description TestDesc1a TestDesc1b TestDesc2a TestDesc2b
Hope this helps to solve your question.

Answer 2

If you ar sure any parent leads to only 1 leaf, it's possible to generate the JSON you want by playing only with string manipulation:
with rel_hier(id, parentid, name, sname, js) as (
select m.id, m.parentid, m.name, m.sname,
CAST(CASE WHEN m.parentid IS NULL THEN
CONCAT('"' , m.sname , '"') ELSE
CONCAT('{"' , m.name , '" : "' , m.sname , '"}') END AS VARCHAR(2000))
js
from Test m
where not exists(select 1 from Test t1 where t1.parentid = m.id)
union all
select m.id, m.parentid, m.name, m.sname,
CAST(CASE WHEN m.parentid IS NULL THEN r.js ELSE CONCAT('{"' , m.name ,
'" : ' , r.js , '}') END AS VARCHAR(2000)) js
from rel_hier r
join Test m on m.id = r.parentid
)
SELECT name, js as sname FROM rel_hier r
WHERE parentid IS NULL
;
name sname
aaa "bbb"
adf {"aad" : {"asdsaa" : "bf"}}
But you should also better explain the substitution rules for a number of levels > 3.