Get all parents for a child

Question

I want to retrieve the parentid of an id, if that parentid has a parent again retrieve it, and so on. Kind of hierarchy table.

id----parentid
1-----1
5-----1         


        

Answer 1

you didn't mention the desired output and input. However you can try like this,

Declare @t table (id int ,parentid int)
insert into @t
select 1,1 union all
select 5,1 union all
select 47894,5 union all
select 47897,47894 

;With CTE as
(
select * from @t where id=1
union all
Select a.* from @t a inner join cte b
 on b.id=a.parentid and
a.id<>b.id
)
select * from cte