In SQL Server 2008;
I have a tree. I need to get all child nodes of node n (see diagram) and all child nodes of these child nodes, etc until the leaf nodes which is fairly trivial. I also need to be able to say 'Take node o, go up the tree until we reach m and because m is a child of node n set some property of node o to some property of node m. Node o could be 3 levels deep (as illustrated) or 45 levels deep, x levels deep.
This gets all children of a given node (or area)
--Return all sub-area structure of an area:
WITH temp_areas (ParentAreaID, AreaID, [Name], [Level]) AS
(
SELECT ParentAreaID, AreaID, [Name], 0
FROM lib_areas WHERE AreaID = #AreaID
UNION ALL
SELECT B.ParentAreaID, B.AreaID, B.[Name], A.Level + 1
FROM temp_areas AS A, lib_areas AS B
WHERE A.AreaID = B.ParentAreaID
)
INSERT INTO #files (id) SELECT fileid FROM lib_filesareasxref where areaid in (select areaid from temp_areas)
while exists (select * from #files)
begin
select top 1
#ID = id
from
#files ORDER BY id DESC
delete from #files where id = #id
This will track back from #node_o until it reaches #node_m or it reaches the top of the tree (if #node_m is not above #node_o).
WITH
parents
AS
(
SELECT
A.ParentAreaID, A.AreaID, A.[Name], 0
FROM
lib_areas AS A
WHERE
A.AreaID = #node_o
UNION ALL
SELECT
A.ParentAreaID, A.AreaID, A.[Name], B.Level + 1
FROM
lib_areas AS A
INNER JOIN
parents AS B
ON A.AreaID = B.ParentAreaID
WHERE
B.AreaID <> #node_m
)
SELECT
*
FROM
parents
I'd propose using a HierarchyID data type in your table, and using the GetAncestor method
Related
I have 2 tables.
One is bom_master:
CHILD
PARENT
1-111
66-6666
2-222
77-7777
2-222
88-8888
3-333
99-9999
Another one is library:
FileName
Location
66-6666_A.step
S:\ABC
77-7777_C~K1.step
S:\DEF
And I want to find out if the child's parents have related files in the library.
Expected Result:
CHILD
PARENT
FileName
1-111
66-6666
66-6666_A.step
2-222
77-7777
77-7777_C~K1.step
Tried below lines but return no results. Any comments? Thank you.
WITH temp_parent_PN(parentPN)
AS
(
SELECT
[PARENT]
FROM [bom_master]
where [bom_master].[CHILD] in ('1-111','2-222')
)
SELECT s.[filename]
FROM [library] s
WHERE EXISTS
(
SELECT
*
FROM temp_parent_PN b
where s.[filename] LIKE '%'+b.[parentPN]+'%'
)
If you have just one level of dependencies use the join solution proposed by dimis164.
If you have deeper levels you could use recursive queries allowed by WITH clause (
ref. WITH common_table_expression (Transact-SQL)).
This is a sample with one more level of relation in bom_master (you could then join the result of the recursive query with library as you need).
DECLARE #bom_master TABLE (Child NVARCHAR(MAX), Parent NVARCHAR(MAX));
INSERT INTO #bom_master VALUES
('1-111', '66-666'),
('2-222', '77-777'),
('3-333', '88-888'),
('4-444', '99-999'),
('A-AAA', '1-111');
WITH
leaf AS ( -- Get the leaf elements (elements without a child)
SELECT Child FROM #bom_master b1
WHERE NOT EXISTS (SELECT * FROM #bom_master b2 WHERE b2.Parent = b1.Child) ),
rec(Child, Parent, Level) AS (
SELECT b.Child, b.Parent, Level = 1
FROM #bom_master b
JOIN leaf l ON l.Child = b.Child
UNION ALL
SELECT rec.Child, b.Parent, Level = rec.Level + 1
FROM rec
JOIN #bom_master b
ON b.Child = rec.Parent )
SELECT * FROM rec
I think you don't have to use exists. The problem is that you need to substring to match the join.
Have a look at this:
SELECT b.CHILD, b.PARENT, l.[FileName]
FROM [bom_master] b
INNER JOIN [library] l ON b.PARENT = SUBSTRING(l.FileName,1,7)
I have run into this a couple of times where a client is able to import data into a catalog with parent child relationships and I run into problems with said relationships. I need to find a way to prevent the following:
Object 1 has a child of Object 2
Object 2 has a child of Object 3
Object 3 has a child of Object 1
This throws the server into an infinite recursive loop and ultimately brings it to its knees. I can't seem to wrap my head around a SQL query that I could use to detect such recursive madness. The problem is prevalent enough that I need to find some solution. I've tried queries using CTE, nested selects/sub-selects and just can't seem to write one that will solve this issue. Any help would be greatly appreciated.
with recursive parents as (
select
s.id,
s.parent_id,
1 as depth
from categories s
where s.id = <passed in id>
union all
select
t.id,
t.parent_id,
c.depth + 1 as depth
from categories t
inner join parents c
on t.id = c.parent_id
where t.id <> t.parent_id)
select distinct parent_id from parents where parent_id <> 0 order by depth desc
This is what I finally came up with to "detect" a cycle condition
with recursive find_cycle as (
select
categories_id,
parent_id,
0 depth
from
categories
where categories_id = <passed in id>
union all
select
f.categories_id,
c.parent_id,
f.depth + 1
from
categories c
inner join find_cycle f
ON f.parent_id = c.categories_id
where c.parent_id <> c.categories_id
and f.parent_id <> f.categories_id
)
select
f.parent_id as categories_id,
c.parent_id
from find_cycle f
inner join categories c
on f.parent_id = c.categories_id
where exists (
select
1
from find_cycle f
inner join categories c
on f.parent_id = c.categories_id
where f.parent_id = <passed in id>)
order by depth desc;
It will return rows with the offending path and no rows if no cycle detected. Thanks for all the tips folks.
Here is the MariaDB function I came up with that will return 0 if there is not a cycle and 1 if there is a cycle for the id passed in to the function.
create function `detect_cycle`(id int, max_depth int) RETURNS tinyint(1)
begin
declare cycle_exists int default 0;
select (case when count(*) = 1 then 0 else 1 end) into cycle_exists
from
(
with recursive find_cycle as (
select
categories_id,
parent_id,
0 depth
from
categories
where categories_id = id
union all
select
f.categories_id,
c.parent_id,
f.depth + 1
from
categories c
inner join find_cycle f
ON f.parent_id = c.categories_id
where
c.parent_id <> c.categories_id
and f.parent_id <> f.categories_id
and f.depth < max_depth
)
select
c.parent_id
from find_cycle f
inner join categories c
on f.parent_id = c.categories_id
order by depth desc
limit 1
) __temp
where parent_id = 0;
return cycle_exists;
end;
This can then be called by executing
select categories_id, detect_cycle(categories_id, 5) as cycle_exists
from categories
where categories_id = <whatever id you want to check for a cycle condition>;
Here is a stored procedure that will accomplish the same thing but is generic enough to handle any table, id column, parent column combination.
CREATE PROCEDURE `detect_cycle`(table_name varchar(64), id_column varchar(32), parent_id_column varchar(32), max_depth int)
BEGIN
declare id int default 0;
declare sql_query text default '';
declare where_clause text default '';
declare done bool default false;
declare id_cursor cursor for select root_id from __temp_ids;
declare continue handler for not found set done = true;
drop temporary table if exists __temp_ids;
create temporary table __temp_ids(root_id int not null primary key);
set sql_query = concat('
insert into __temp_ids
select
`',id_column,'`
from ',table_name);
prepare statement from sql_query;
execute statement;
drop temporary table if exists __temp_cycle;
create temporary table __temp_cycle (id int not null, parent_id int not null);
open id_cursor;
id_loop: loop
fetch from id_cursor into id;
if done then
leave id_loop;
end if;
set where_clause = concat('where `',id_column,'` = ',id);
set sql_query = concat('
insert into __temp_cycle
select
t.`',id_column,'`,
t.`',parent_id_column,'`
from
(
with recursive find_cycle as (
select
`',id_column,'`,
`',parent_id_column,'`,
0 depth
from
`',table_name,'`
',where_clause,'
union all
select
f.`',id_column,'`,
c.`',parent_id_column,'`,
f.depth + 1
from
`',table_name,'` c
inner join find_cycle f
ON f.`',parent_id_column,'` = c.`',id_column,'`
where
c.`',parent_id_column,'` <> c.`',id_column,'`
and f.`',parent_id_column,'` <> f.`',id_column,'`
and f.depth < ',max_depth,'
)
select
c.`',id_column,'`,
c.`',parent_id_column,'`
from find_cycle f
inner join `',table_name,'` c
on f.`',parent_id_column,'` = c.`',id_column,'`
order by depth desc
limit 1
) t
where t.`',parent_id_column,'` > 0');
prepare statement from sql_query;
execute statement;
end loop;
close id_cursor;
deallocate prepare statement;
select distinct
*
from __temp_cycle;
drop temporary table if exists __temp_ids;
drop temporary table if exists __temp_cycle;
END
usage:
call detect_cycle(table_name, id_column, parent_id_column, max_depth);
This will return a result set of all cycle conditions within the given table.
Looks like you have this figured out to stop a cycling event but are looking for ways to identify a cycle. In that case, consider using a path:
with recursive parents as (
select
s.id,
s.parent_id,
1 as depth,
CONCAT(s.id,'>',s.parent_id) as path,
NULL as cycle_detection
from categories s
where s.id = <passed in id>
union all
select
t.id,
t.parent_id,
c.depth + 1 as depth,
CONCAT(c.path, '>', t.parent_id),
CASE WHEN c.path LIKE CONCAT('%',t.parent_id,'>%') THEN 'cycle' END
from categories t
inner join parents c
on t.id = c.parent_id
where t.id <> t.parent_id)
select distinct parent_id, cycle_detection from parents where parent_id <> 0 order by depth desc
I may be a bit off my syntax since it's been forever since I wrote mysql/mariadb syntax, but this is the basic idea. Capture the path that the recursion took and then see if your current item is already in the path.
If the depth of the resulting tree is not extremely deep then you can detect cycles by storing the bread crumbs that the recursive CTE is walking. Knowing the bread crumbs you can detect cycles easily.
For example:
with recursive
n as (
select id, parent_id, concat('/', id, '/') as path
from categories where id = 2
union all
select c.id, c.parent_id, concat(n.path, c.id, '/')
from n
join categories c on c.parent_id = n.id
where n.path not like concat('%/', c.id, '/%') -- cycle pruning here!
)
select * from n;
Result:
id parent_id path
--- ---------- -------
2 1 /2/
3 2 /2/3/
1 3 /2/3/1/
See running example at DB Fiddle.
I have a table, let's say it looks like this:
c | p
=====
|1|3|
|2|1|
|7|5|
c stands for current and p stands for parent
Given a c value of 2 I would return its top most ancestor (which has no parent) this value is 3. Since this is a self referencing table, I figured using CTE would be the best method however I am very new to using it. Nevertheless, I gave it a shot:
WITH Tree(this, parent) AS
( SELECT c ,p
FROM myTable
WHERE c = '2'
UNION ALL
SELECT M.c ,M.p
FROM myTable M
JOIN Tree T ON T.parent = M.c )
SELECT parent
FROM Tree
However this returns:
1
3
I only want 3 though. I have tried putting WHERE T.parent <> M.c but that doesn't entirely make sense. Neadless to say, I am a little confused for how to isolate the grandparent.
DECLARE #Table AS TABLE (Child INT, Parent INT)
INSERT INTO #Table VALUES (1,3),(2,1),(7,5)
;WITH cteRecursive AS (
SELECT
OriginalChild = Child
,Child
,Parent
,Level = 0
FROM
#Table
WHERE
Child = 2
UNION ALL
SELECT
c.OriginalChild
,t.Child
,t.Parent
,Level + 1
FROM
cteRecursive c
INNER JOIN #Table t
ON c.Parent = t.Child
)
SELECT TOP 1 TopAncestor = Parent
FROM
cteRecursive
ORDER BY
Level DESC
Use a recursive cte to Recuse up the tree until you cannot. Keep track of the Level of recursion, then take the last level of recursions parent and you have the top ancestor.
And just because I wrote it I will add in if you wanted to find the top ancestor of every child. The concept is still the same but you would need to introduce a row_number() to find the last level that was recursed.
DECLARE #Table AS TABLE (Child INT, Parent INT)
INSERT INTO #Table VALUES (1,3),(2,1),(7,5),(5,9)
;WITH cteRecursive AS (
SELECT
OriginalChild = Child
,Child
,Parent
,Level = 0
FROM
#Table
UNION ALL
SELECT
c.OriginalChild
,t.Child
,t.Parent
,Level + 1
FROM
cteRecursive c
INNER JOIN #Table t
ON c.Parent = t.Child
)
, cteTopAncestorRowNum AS (
SELECT
*
,TopAncestorRowNum = ROW_NUMBER() OVER (PARTITION BY OriginalChild ORDER BY Level DESC)
FROM
cteRecursive
)
SELECT
Child = OriginalChild
,TopMostAncestor = Parent
FROM
cteTopAncestorRowNum
WHERE
TopAncestorRowNum = 1
I have seen many examples of the getting all the child nodes (including current node) in SQL using the CTE. Simple example is below:
;WITH #results AS
(
SELECT ChildId,
ParentId
FROM History
WHERE ChildId= #selected
UNION ALL
SELECT t.ChildId,
t.ParentId
FROM History t
INNER JOIN #results r ON r.ExpirationList = t.ParentId
)
SELECT *
FROM #results;
The above query gives me all the child nodes for a given node. For eg:
A -> B -> C -> D -> E and I pass #selected = "C", then I get results as C -> D -> E.
My question is how do I get the complete chain, irrespective of what I pass.
If #selected = "D", then I want results as A -> B -> C -> D -> E and
if #selected = "A", then I want results as A -> B -> C -> D -> E.
I want both parent and child nodes for the given nodes. Can someone help me with the query for the same?
This should work:
;WITH #results1 AS
(
SELECT ChildId,
ParentId
FROM History
WHERE ChildId= #selected
UNION ALL
SELECT t.ChildId,
t.ParentId
FROM History t
INNER JOIN #results1 r ON r.ExpirationList = t.ParentId
)
,#results2 AS
(
SELECT ChildId,
ParentId
FROM History
WHERE ChildId= #selected
UNION ALL
SELECT t.ChildId,
t.ParentId
FROM History t
INNER JOIN #results2 r ON t.ExpirationList = r.ParentId
)
SELECT *
FROM #results1
UNION
SELECT *
FROM #results2
I combine the 2 CTEs (one for finding child and other for parents) into the common temp table and then pulled out the records from the same.
I referred to the below codeproject post which was helpful.
http://www.codeproject.com/Articles/818694/SQL-queries-to-manage-hierarchical-or-parent-child
Thanks for your suggestions and responses.
I'm trying to write a recursive query in SQL Server that basically lists a parent-child hierarchy from a given parent. A parent can have multiple children and a child can belong to multiple parents so it is stored in a many-to-many relation.
I modified the following query from another somewhat related question, however this doesn't go all the way up to the tree and only selects the first level child...
DECLARE #ObjectId uniqueidentifier
SET #ObjectId = '1A213431-F83D-49E3-B5E2-42AA6EB419F1';
WITH Tree AS
(
SELECT A.*
FROM Objects_In_Objects A
WHERE A.ParentObjectId = #ObjectId
UNION ALL
SELECT B.*
FROM Tree A
JOIN Objects_In_Objects B
ON A.ParentObjectId = B.ObjectId
)
SELECT *
FROM Tree
INNER JOIN Objects ar on tree.ObjectId = ar.ObjectId
Does anyone know how to modify the query to go all the way down the 'tree'? Or is this not possible using the above construction?
Objects
Columns: ObjectId | Name
Objects_In_Objects
Columns: ObjectId | ParentObjectId
Sample data:
Objects
ObjectId | Name
1A213431-F83D-49E3-B5E2-42AA6EB419F1 | Main container
63BD908B-54B7-4D62-BE13-B888277B7365 | Sub container
71526E15-F713-4F03-B707-3F5529D6B25E | Sub container 2
ADA9A487-7256-46AD-8574-0CE9475315E4 | Object in multiple containers
Objects In Objects
ObjectId | ParentObjectId
ADA9A487-7256-46AD-8574-0CE9475315E4 | 71526E15-F713-4F03-B707-3F5529D6B25E
ADA9A487-7256-46AD-8574-0CE9475315E4 | 63BD908B-54B7-4D62-BE13-B888277B7365
63BD908B-54B7-4D62-BE13-B888277B7365 | 1A213431-F83D-49E3-B5E2-42AA6EB419F1
71526E15-F713-4F03-B707-3F5529D6B25E | 1A213431-F83D-49E3-B5E2-42AA6EB419F1
Such a recursive CTE (Common Table Expression) will goo all the way .
Try this:
;WITH Tree AS
(
SELECT A.ObjectID, A.ObjectName, o.ParentObjectID, 1 AS 'Level'
FROM dbo.Objects A
INNER JOIN dbo.Objects_In_Objects o ON A.ObjectID = o.ParentObjectID
WHERE A.ObjectId = #ObjectId -- use the A.ObjectId here
UNION ALL
SELECT A2.ObjectID, A2.ObjectName, B.ParentObjectID, t.Level + 1 AS 'Level'
FROM Tree t
INNER JOIN dbo.Objects_In_Objects B ON B.ParentObjectID = t.ObjectID
INNER JOIN dbo.Objects A2 ON A2.ObjectId = B.ObjectId
)
SELECT *
FROM Tree
INNER JOIN dbo.Objects ar on tree.ObjectId = ar.ObjectId
If you change this - does this work for you now? (I added a Level column - typically helps to understand the "depth" in the hierarchy for every row)
I do seem to get the proper output on my SQL Server instance, at least...
declare #Objects_In_Objects table
(
ObjectID uniqueidentifier,
ParentObjectId uniqueidentifier
)
declare #Objects table
(
ObjectId uniqueidentifier,
Name varchar(50)
)
insert into #Objects values
('1A213431-F83D-49E3-B5E2-42AA6EB419F1', 'Main container'),
('63BD908B-54B7-4D62-BE13-B888277B7365', 'Sub container'),
('71526E15-F713-4F03-B707-3F5529D6B25E', 'Sub container 2'),
('ADA9A487-7256-46AD-8574-0CE9475315E4', 'Object in multiple containers')
insert into #Objects_In_Objects values
('ADA9A487-7256-46AD-8574-0CE9475315E4', '71526E15-F713-4F03-B707-3F5529D6B25E'),
('ADA9A487-7256-46AD-8574-0CE9475315E4', '63BD908B-54B7-4D62-BE13-B888277B7365'),
('63BD908B-54B7-4D62-BE13-B888277B7365', '1A213431-F83D-49E3-B5E2-42AA6EB419F1'),
('71526E15-F713-4F03-B707-3F5529D6B25E', '1A213431-F83D-49E3-B5E2-42AA6EB419F1')
DECLARE #ObjectId uniqueidentifier
SET #ObjectId = '1A213431-F83D-49E3-B5E2-42AA6EB419F1';
WITH Tree AS
(
SELECT A.ObjectID,
A.ParentObjectId
FROM #Objects_In_Objects A
WHERE A.ParentObjectId = #ObjectId
UNION ALL
SELECT B.ObjectID,
B.ParentObjectId
FROM Tree A
JOIN #Objects_In_Objects B
ON B.ParentObjectId = A.ObjectId
)
SELECT *
FROM Tree
INNER JOIN #Objects ar on tree.ObjectId = ar.ObjectId;
Is this what you are looking for? https://data.stackexchange.com/stackoverflow/q/111357/
Can this help you ?
http://www.aghausman.net/sql_server/storingretrieving-hierarchical-data-in-sql-server-database.html