Get all children and grandchildren from either of the two parent columns - sql

Question

I need to find all the parent-children relationships, which are all linked to my primary column ID
I have tried the below thus far, but that works with only one column.
WITH tb (id,Name, Level, Path, Parent)
AS
(
SELECT
id,Name, 1 AS Level,
CAST('/'+Name as nvarchar(max)) as Path,
CAST(NULL as nvarchar(max)) as Parent
FROM krishtest
WHERE parent1 IS NULL
UNION All
SELECT
e.id,e.Name, x.Level + 1 AS Level, x.Path + '/' + e.Name as Path,
REVERSE(SUBSTRING( REVERSE(x.[Path]) ,0 , CHARINDEX( '/', REVERSE(x.[Path])) )) as [Parent]
FROM krishtest e
JOIN tb x ON x.id = e.parent1
)
SELECT Name, Level, Path, Parent FROM tb

Answer 1

As i understand the parent can be in either parent1 or parent 2 column; then in such case your query should be as below
The only change is use of keyword COALSECE which takes the first non NULL value from the list.
bug assumption is that both parent1 and parent2 are not (Non-Null) together.
See live demo
;
WITH tb (id,Name, Level, Path, Parent)
AS
(
SELECT
id,Name, 1 AS Level,
CAST('/'+Name as nvarchar(max)) as Path,
CAST(NULL as nvarchar(max)) as Parent
FROM krishtest
WHERE COALESCE(parent1,parent2) IS NULL
UNION All
SELECT
e.id,e.Name, x.Level + 1 AS Level, x.Path + '/' + e.Name as Path,
REVERSE(SUBSTRING( REVERSE(x.[Path]) ,0 , CHARINDEX( '/', REVERSE(x.[Path])) )) as [Parent]
FROM krishtest e
JOIN tb x ON x.id = COALESCE(e.parent1,e.parent2)
)
SELECT Name, Level, Path, Parent FROM tb