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I am trying to build a deep recursive self-join query. Having the table like:
Id | ParentId
1 | NULL
2 | 1
3 | 1
4 | 2
5 | 3
6 | 8
7 | 9
For Id 1 my query should be fetching 1,2,3,4,5 since they are either the children of 1 or children of the children of 1. In the given example 6 and 7 should not be included in the query result.
I tried using CTE but I am getting tons of duplicates:
WITH CTE AS (
SELECT Id, ParentId
FROM dbo.Table
WHERE ParentId IS NULL
UNION ALL
SELECT t.Id, t.ParentId
FROM dbo.Table t
INNER JOIN CTE c ON t.ParentId = c.Id
)
SELECT * FROM CTE
Ideas?
You can try to use DISTINCT to filter duplicate rows.
;WITH CTE AS (
SELECT Id, ParentId
FROM T
WHERE ParentId IS NULL
UNION ALL
SELECT t.Id, t.ParentId
FROM T
INNER JOIN CTE c ON t.ParentId = c.Id
)
SELECT DISTINCT Id, ParentId
FROM CTE
Try the following query with CTE where you can set parentId by #parentID:
DECLARE #parentID INT = 1
;WITH cte AS
(
SELECT
t.ID
, t.ParentId
FROM #table t
),
cteParent AS
(
SELECT
t.ID
, t.ParentId
FROM #table t
WHERE t.ParentId IN (SELECT t1.ID FROM #table t1 WHERE T1.ParentId = #parentID)
)
SELECT
DISTINCT c1.ID
, c1.ParentId
FROM cte c1
INNER JOIN cte c2 ON c2.ParentId = c1.ID
UNION ALL
SELECT *
FROM cteParent
And the sample data:
DECLARE #table TABLE
(
ID INT
, ParentId INT
)
INSERT INTO #table
(
ID,
ParentId
)
VALUES
(1, NULL )
, (2, 1 )
, (3, 1 )
, (4, 2 )
, (5, 3 )
, (6, 8 )
, (7, 9 )
OUTPUT:
ID ParentId
1 NULL
2 1
3 1
4 2
5 3
I don't see duplicates.
Your code returns the following on the data you provided:
Id ParentId
1
2 1
3 1
5 3
4 2
which is what you want.
Here is a db<>fiddle.
Here is the code:
WITH t as (
SELECT *
FROM (VALUES (1, NULL), (2, 1), (3, 1), (4, 2), (5, 3), (6, 8), (7, 9)
) v(id, parentId)
),
CTE AS (
SELECT Id, ParentId
FROM t
WHERE ParentId IS NULL
UNION ALL
SELECT t.Id, t.ParentId
FROM t
INNER JOIN CTE c ON t.ParentId = c.Id
)
SELECT *
FROM CTE;
If you are getting duplicates in your actual result set, then you presumably have duplicates in your original table. I would recommend removing them before doing the recursive logic:
with t as (
select distinct id, parentid
from <your query>
),
. . .
Then run the recursive logic.
Try this sql script which result Parent Child Hierarchy
;WITH CTE(Id , ParentId)
AS
(
SELECT 1 , NULL UNION ALL
SELECT 2 , 1 UNION ALL
SELECT 3 , 1 UNION ALL
SELECT 4 , 2 UNION ALL
SELECT 5 , 3 UNION ALL
SELECT 6 , 8 UNION ALL
SELECT 7 , 9
)
,Cte2
AS
(
SELECT Id ,
ParentId ,
CAST('\'+ CAST(Id AS VARCHAR(MAX))AS VARCHAR(MAX)) AS [Hierarchy]
FROM CTE
WHERE ParentId IS NULL
UNION ALL
SELECT c1.Id ,
c1.ParentId ,
[Hierarchy]+'\'+ CAST(c1.Id AS VARCHAR(MAX)) AS [Hierarchy]
FROM Cte2 c2
INNER JOIN CTE c1
ON c1.ParentId = c2.Id
)
SELECT Id,
RIGHT([Hierarchy],LEN([Hierarchy])-1) AS ParentChildHierarchy
FROM Cte2
GO
Result
Id ParentChildHierarchy
-------------------------
1 1
2 1\2
3 1\3
5 1\3\5
4 1\2\4
This query will help you
CREATE TABLE #table( ID INT, ParentId INT )
INSERT INTO #table(ID,ParentId)
VALUES (1, NULL ), (2, 1 ), (3, 1 ), (4, 2 ), (5, 3 ), (6, 8 ), (7, 9 )
;WITH CTE AS (
SELECT ID FROM #table WHERE PARENTID IS NULL
UNION ALL
SELECT T.ID FROM #table T
INNER JOIN #table T1 ON T.PARENTID =T1.ID
) SELECT * FROM CTE
Example :
when I type :
select number, city from user
The results in the get is 3 rows. How to select the row that I can be automatically filled in 8 rows? What if using a loop ?
Desired Output:
if 3 rows then there are 5 empty rows,
if 4 rows then there are 4 empty rows, etc ..
While I don't understand the cause of this task, anyway you can do it like :
DECLARE #t TABLE ( ID INT )
DECLARE #c INT = 8
INSERT INTO #t
VALUES ( 1 ),
( 2 ),
( 3 );
WITH cte
AS ( SELECT 1 AS rn
UNION ALL
SELECT rn + 1
FROM cte
WHERE rn <= #c
)
SELECT TOP ( #c )
*
FROM ( SELECT ID
FROM #t
UNION ALL
SELECT NULL
FROM cte
) t
ORDER BY ID DESC
Output:
ID
3
2
1
NULL
NULL
NULL
NULL
NULL
This is kind of hard to explain in words but here is an example of what I am trying to do in SQL. I have a query which returns the following records:
ID Z
--- ---
1 A
1 <null>
2 B
2 E
3 D
4 <null>
4 F
5 <null>
I need to filter this query so that each unique record (based on ID) appears only once in the output and if there are multiple records for the same ID, the output should contain the record with the value of Z column being non-null. If there is only a single record for a given ID and it has value of null for column Z the output still should return that record. So the output from the above query should look like this:
ID Z
--- ---
1 A
2 B
2 E
3 D
4 F
5 <null>
How would you do this in SQL?
You can use GROUP BY for that:
SELECT
ID, MAX(Z) -- Could be MIN(Z)
FROM MyTable
GROUP BY ID
Aggregate functions ignore NULLs, returning them only when all values on the group are NULL.
If you need to return both 2-B and 2-E rows:
SELECT *
FROM YourTable t1
WHERE Z IS NOT NULL
OR NOT EXISTS
(SELECT * FROM YourTable t2
WHERE T2.ID = T1.id AND T2.z IS NOT NULL)
SELECT ID
,Z
FROM YourTable
WHERE Z IS NOT NULL
DECLARE #T TABLE ( ID INT, Z CHAR(1) )
INSERT INTO #T
( ID, Z )
VALUES ( 1, 'A' ),
( 1, NULL )
, ( 2, 'B' ) ,
( 2, 'E' ),
( 3, 'D' ) ,
( 4, NULL ),
( 4, 'F' ),
( 5, NULL )
SELECT *
FROM #T
; WITH c AS (SELECT ID, r=COUNT(*) FROM #T GROUP BY ID)
SELECT t.ID, Z
FROM #T t JOIN c ON t.ID = c.ID
WHERE c.r =1
UNION ALL
SELECT t.ID, Z
FROM #T t JOIN c ON t.ID = c.ID
WHERE c.r >=2
AND z IS NOT NULL
This example assumes you want two rows returned for ID = 2.
with tmp (id, cnt_val) as
(select id,
sum(case when z is not null then 1 else 0 end)
from t
group by id)
select t.id, t.z
from t
inner join tmp on t.id = tmp.id
where tmp.cnt_val > 0 and t.z is not null
or tmp.cnt_val = 0 and t.z is null
WITH CTE
AS (
SELECT id
,z
,ROW_NUMBER() OVER (
PARTITION BY id ORDER BY coalesce(z, '') DESC
) rn
FROM #T
)
SELECT id
,z
FROM CTE
WHERE rn = 1
Let's say I have a database schema like this:
RowId ParentId Name
------ ---------- ------
1 NULL Level1
2 NULL Level2
3 1 Leaf1
4 1 Leaf2
5 2 Leaf1
6 3 LeafX
Basically, the tree would look as such:
Level1
Leaf1
LeafX
Leaf2
Level2
Leaf1
I need to extract all ancestor LEVEL of LeafX in the most efficient and dynamic way.
So it will output: Leaf1, Leaf2, and Leaf1 (of Level2)
How do I do this in T-SQL? Thanks
This will give you the result you want.
;with C as
(
select T.rowid,
T.parentid,
T.name,
1 as Lvl
from YourTable as T
where T.parentid is null
union all
select T.rowid,
T.parentid,
T.name,
C.Lvl + 1
from YourTable as T
inner join C
on T.parentid = C.rowid
)
select *
from C
where C.Lvl = (
select C.lvl-1
from C
where C.name = 'LeafX'
)
Update
And this might be faster for you. You have to test on your data.
declare #Level int;
with C as
(
select T.rowid,
T.parentid
from #t as T
where T.name = 'LeafX'
union all
select T.rowid,
T.parentid
from #t as T
inner join C
on T.rowid = C.parentid
)
select #Level = count(*) - 1
from C;
with C as
(
select T.rowid,
T.parentid,
T.name,
1 as Lvl
from #t as T
where T.parentid is null
union all
select T.rowid,
T.parentid,
T.name,
C.Lvl + 1
from #t as T
inner join C
on T.parentid = C.rowid
where C.Lvl < #Level
)
select *
from C
where C.Lvl = #Level;
There's a few methods to do that. My favourite is to create special table Trees_Parents, where you will store every parent for evere node.
So if have structure like that
RowId ParentId Name
------ ---------- ------
1 NULL Level1
2 NULL Level2
3 1 Leaf1
4 1 Leaf2
5 2 Leaf1
6 3 LeafX
your Trees_Parents table will looks like
RowId ParentId
------ ----------
1 1
2 2
3 3
3 1
4 4
4 1
5 5
5 2
6 6
6 1
6 3
then when you need to retrieve all children you just write
select RowID from Trees_Parents where ParentId = 1
I'm storing row self in this table to avoid unions, if you don't need it you can write
select RowID from Trees_Parents where ParentId = 1 and ParentId <> RowId
And for all parents you'll write
select ParentId from Trees_Parents where RowId = 6 and ParentId <> RowId
You can also store Table_Name in table Trees_Parents so you can use it for different tables
Another way is to write recursive WITH clause, but if your tree is big and it's not changing frequently I think it's better to store parents data in additional table
Well you can use recursive solution. You need to get all nodes with Depth = Depth of your node - 1
declare #Temp table (RowId int, ParentId int, Name nvarchar(128))
insert into #Temp
select 1, null, 'Level1' union all
select 2, null, 'Level2' union all
select 3, 1, 'Leaf1' union all
select 4, 1, 'Leaf2' union all
select 5, 2, 'Leaf3' union all
select 6, 3, 'LeafX';
with Parents
as
(
select T.RowId, 0 as Depth from #Temp as T where T.ParentId is null
union all
select T.RowId, P.Depth + 1
from Parents as P
inner join #Temp as T on T.ParentId = P.RowId
)
select T.Name
from Parents as P
outer apply (select TT.Depth from Parents as TT where TT.RowId = 6) as CALC
left outer join #Temp as T on T.RowId = P.RowId
where P.Depth = CALC.Depth - 1
declare #t table(rowid int, parentid int, name varchar(10))
insert #t values(1,NULL,'Level1')
insert #t values(2,NULL,'Level2')
insert #t values(3,1,'Leaf1')
insert #t values(4,1,'Leaf2')
insert #t values(5,2,'Leaf1')
insert #t values(6,3,'LeafX')
;with a as
(
select rowid, parentid, 0 level from #t where name = 'leafx'
union all
select t.rowid, t.parentid, level + 1 from #t t
join a on a.parentid = t.rowid
), b as
(
select rowid, parentid,name, 0 level from #t where parentid is null
union all
select t.rowid, t.parentid,t.name, level + 1
from b join #t t on b.rowid = t.parentid
)
select rowid, parentid, name from b
where level = (select max(level)-1 from a)
rowid parentid name
5 2 Leaf1
3 1 Leaf1
4 1 Leaf2
It would be easier to explain with an example. Suppose I wanted to get at most 5 items per group.
My input would be a table looking like this:
Item Count
A 2
A 3
A 3
B 4
B 4
B 5
C 1
And my desired output would look like this:
Item Count
A 5
A>5 3
B 4
B>5 9
C 1
An alternative output that I could also work with would be
Item Count RunningTotal
A 2 2
A 3 5
A 3 8
B 4 4
B 4 8
B 5 13
C 1 1
I can use ROW_NUMBER() to get the top X records in each group, however my requirement is to get the top X items for each group, not X records. My mind is drawing a blank as to how to do this.
declare #yourTable table (item char(1), [count] int)
insert into #yourTable
select 'A', 2 union all
select 'A', 3 union all
select 'A', 3 union all
select 'B', 4 union all
select 'B', 4 union all
select 'B', 5 union all
select 'C', 1
;with cte(item, count, row) as (
select *, row_number() over ( partition by item order by item, [count])
from #yourTable
)
select t1.Item, t1.Count, sum(t2.count) as RunningTotal from cte t1
join cte t2 on t1.item = t2.item and t2.row <= t1.row
group by t1.item, t1.count, t1.row
Result:
Item Count RunningTotal
---- ----------- ------------
A 2 2
A 3 5
A 3 8
B 4 4
B 4 8
B 5 13
C 1 1
Considering the clarifications from your comment, you should be able to produce the second kid of output from your post by running this query:
select t.Item
, t.Count
, (select sum(tt.count)
from mytable tt
where t.item=tt.item and (tt.creating_user_priority < t.creating_user_priority or
( tt.creating_user_priority = t.creating_user_priority and tt.created_date < t.createdDate))
) as RunningTotal
from mytable t
declare #yourTable table (item char(1), [count] int)
insert into #yourTable
select 'A', 2 union all
select 'A', 3 union all
select 'A', 3 union all
select 'B', 4 union all
select 'B', 4 union all
select 'B', 5 union all
select 'C', 1
;with cte(item, count, row) as (
select *, row_number() over ( partition by item order by item, [count])
from #yourTable
)
select t1.row, t1.Item, t1.Count, sum(t2.count) as RunningTotal
into #RunTotal
from cte t1
join cte t2 on t1.item = t2.item and t2.row <= t1.row
group by t1.item, t1.count, t1.row
alter table #RunTotal
add GrandTotal int
update rt
set GrandTotal = gt.Total
from #RunTotal rt
left join (
select Item, sum(Count) Total
from #RunTotal rt
group by Item) gt
on rt.Item = gt.Item
select Item, max(RunningTotal)
from #RunTotal
where RunningTotal <= 5
group by Item
union
select a.Item + '>5', total - five
from (
select Item, max(GrandTotal) total
from #RunTotal
where GrandTotal > 5
group by Item
) a
left join (
select Item, max(RunningTotal) five
from #RunTotal
where RunningTotal <= 5
group by Item
) b
on a.Item = b.Item
I've updated the accepted answer and got your desired result.
SELECT Item, SUM(Count)
FROM mytable t
GROUP BY Item
HAVING SUM(Count) <=5
UNION
SELECT Item, 5
FROM mytable t
GROUP BY Item
HAVING SUM(Count) >5
UNION
SELECT t2.Item + '>5', Sum(t2.Count) - 5
FROM mytable t2
GOUP BY Item
HAVING SUM(Count) > 5
ORDER BY 1, 2
select 'A' as Name, 2 as Cnt
into #tmp
union all select 'A',3
union all select 'A',3
union all select 'B',4
union all select 'B',4
union all select 'B',5
union all select 'C',1
select Name, case when sum(cnt) > 5 then 5 else sum(cnt) end Cnt
from #tmp
group by Name
union
select Name+'>5', sum(cnt)-5 Cnt
from #tmp
group by Name
having sum(cnt) > 5
Here is what I have so far. I know it's not complete but... this should be a good starting point.
I can get your second output by using a temp table and an update pass:
DECLARE #Data TABLE
(
ID INT IDENTITY(1,1) PRIMARY KEY
,Value VARCHAR(5)
,Number INT
,Total INT
)
INSERT INTO #Data (Value, Number) VALUES ('A',2)
INSERT INTO #Data (Value, Number) VALUES ('A',3)
INSERT INTO #Data (Value, Number) VALUES ('A',3)
INSERT INTO #Data (Value, Number) VALUES ('B',4)
INSERT INTO #Data (Value, Number) VALUES ('B',4)
INSERT INTO #Data (Value, Number) VALUES ('B',5)
INSERT INTO #Data (Value, Number) VALUES ('C',1)
DECLARE
#Value VARCHAR(5)
,#Count INT
UPDATE #Data
SET
#Count = Total = CASE WHEN Value = #Value THEN Number + #Count ELSE Number END
,#Value = Value
FROM #Data AS D
SELECT
Value
,Number
,Total
FROM #Data
There may be better ways, but this should work.