How to select parents and children rows in SQL Server - sql

Question

I want to select all itens related to user_id 53 (parents and children) from the following table. It should be: 1, 2, 4, 8, 9.
my_table
--------------------------------------------
id parent_id user_id sequence depth
--------------------------------------------
1 null 50 1 1
2 1 52 1.2 2
3 1 52 1.3 2
4 2 53 1.2.4 3
5 2 52 1.2.5 3
6 3 52 1.3.6 3
7 3 51 1.3.7 3
8 4 51 1.2.4.8 4
9 4 51 1.2.4.9 4
With CTE I could select all children or parents, but I could'nt select children and parents with just one query. Below is the cte I'm using to select children.
Item and children
with cte as (
select t.id, t.parent_id, t.user_id
from my_table t
where t.user_id=53
union all
select t.id, t.parent_id, t.user_id
from my_table t
inner join cte c on (c.parent_id=t.id)
)
select t.* from cte t;
Item and parents
with cte as (
select t.id, t.parent_id, t.user_id
from my_table t
where t.user_id=53
union all
select t.id, t.parent_id, t.user_id
from my_table t
inner join cte c on (c.id=t.parent_id)
)
select t.* from cte t;
Thanks.

Answer 1

It is very convenient that you have the sequences. The parents have a sequence matching an initial subset of the one you are looking for. The same is true for the children, but in reverse.
The following comes close to what you want:
select mt.*
from (select sequence from my_table where USER_ID = 53) theone join
my_table mt
on mt.sequence like theone.sequence+ '%' or
theone.sequence like mt.sequence + '%'
However, you have to be careful with 10 matching 1, for instance. So, let's add an additional period where appropriate:
select mt.*
from (select sequence from my_table where USER_ID = 53) theone join
my_table mt
on mt.sequence like theone.sequence+ '.%' or
theone.sequence like mt.sequence + '.%'

Answer 2

The problem here is, that you want a recursive SELECT. A DBMS is not made for such a query. But it's of course possible.
SELECT t1.* FROM Table1 t1 WHERE user_id = 53
UNION ALL
SELECT t2.* FROM Table1 t1, Table1 t2
WHERE
(t1.id = t2.parent_id OR t1.parent_id = t2.id) AND t1.user_id = 53
This query would give you each 1st degree relative.
For a recursive SELECT, have a look here: Recursive select in SQL
Solution for your query here: http://sqlfiddle.com/#!6/e1542/10/0
with cte as (
select t.id, t.parent_id, t.user_id
from Table1 t
where t.user_id=53
),
cte1 as (
select t.id, t.parent_id, t.user_id
from cte t
union all
select t.id, t.parent_id, t.user_id
from Table1 t
inner join cte1 c on (c.parent_id=t.id)
),
cte2 as (
select t.id, t.parent_id, t.user_id
from cte t
union all
select t.id, t.parent_id, t.user_id
from Table1 t
inner join cte2 c on (c.id=t.parent_id)
)
select t.* from cte1 t
UNION
select t.* from cte2 t

Answer 3

declare #Rownumber int;
CREATE TABLE #GetSeqUser (
RowNumber int,
UserId int,
)
INSERT INTO #GetSeqUser Select ROW_NUMBER() OVER(ORDER BY EmpId ASC) AS ROWNUMBER, EmpId FROM dbo.TreeSystem
set #Rownumber = (select ROWNUMBER from #GetSeqUser where UserId = 3 )
set #Rownumber = #Rownumber + 1
select UserId from #GetSeqUser where ROWNUMBER = #Rownumber

Answer 4

declare #Rownumber int;
CREATE TABLE #GetSeqUser (
RowNumber int,
UserId int,
)
INSERT INTO #GetSeqUser Select ROW_NUMBER() OVER(ORDER BY EmpId ASC) AS ROWNUMBER, EmpId FROM dbo.TreeSystem
set #Rownumber = (select ROWNUMBER from #GetSeqUser where UserId = 3 )
set #Rownumber = #Rownumber + 1
select UserId from #GetSeqUser where ROWNUMBER = #Rownumber