Query to get the parent level and child level hierarchy data of a particular account.

Declare @TestTable Table
(
ID int,
Name varchar(50),
ParentID int
)

Insert into @TestTable values
(1,'A',null),
(2,'Aa',1),
(3,'Aaa',1),
(4,'Ab',2),
(5,'Abb',4),
(6,'B',null),
(7,'Ba',6),
(8,'Bbb',7),
(9,'Abc',4),
(10,'Acc',9)


Declare @ID int = 4

;with cte
(
ID,Name,ParentID
)
As
(
Select ID,Name,ParentID
From @TestTable  where ID = @ID

Union All

Select a.ID , a.Name,a.ParentID
from cte c inner join @TestTable a on c.ParentID = a.ID
)
,
cte1
(
ID,Name,ParentID
)
As
(
Select ID,Name,ParentID
From cte where ParentID is null

Union All

Select a.ID , a.Name,a.ParentID
from cte1 c inner join @TestTable a on a.ParentID = c.ID
)

Select * from Cte1 Option (MAXRECURSION 32767)