Question

hi i need a query to do this
my table data

ID        ParentID         DATA
--------------------------------
1             -1             a
2              1             b
3              2             c
4              3             d
5              3             f

and what ineed a query that take a ID as parameter and return all recursively childs and Itself

parameter : (ID=2)

return must be :

ID        ParentID         DATA
--------------------------------
2              1             b
3              2             c
4              3             d
5              3             f

Answer 1

This should do it for you:

create table #temp 
(
    id int, 
    parentid int,
    data varchar(1)
)
insert #temp (id, parentid, data) values (1, -1, 'a')
insert #temp (id, parentid, data) values (2,1, 'b')
insert #temp (id, parentid, data) values  (3,2, 'c')
insert #temp (id, parentid, data) values  (4,3, 'd')
insert #temp (id, parentid, data) values  (5,3, 'f')

; with cte as (
    select  id, parentid, data, id as topparent
    from    #temp
    union all
    select  child.id, child.parentid, child.data, parent.topparent
    from    #temp child
    join    cte parent
    on      parent.id = child.parentid

)
select  id, parentid, data
from    cte
where topparent = 2

drop table #temp

EDIT or you can put the WHERE clause inside the first select

create table #temp 
(
    id int, 
    parentid int,
    data varchar(1)
)
insert #temp (id, parentid, data) values (1, -1, 'a')
insert #temp (id, parentid, data) values (2,1, 'b')
insert #temp (id, parentid, data) values  (3,2, 'c')
insert #temp (id, parentid, data) values  (4,3, 'd')
insert #temp (id, parentid, data) values  (5,3, 'f')

; with cte as (
    select  id, parentid, data, id as topparent
    from    #temp
    WHERE id = 2
    union all
    select  child.id, child.parentid, child.data, parent.topparent
    from    #temp child
    join    cte parent
    on      parent.id = child.parentid

)
select  id, parentid, data
from    cte

drop table #temp

Results:

id  parentid      data
2   1              b
3   2              c
4   3              d
5   3              f