I have a table structure like so (simplified):
Id ParentId Name Desc
------------------------------
1 NULL A
2 NULL B
3 1 A1
4 1 A2
5 2 B1
It's a big table and can be very painful to look through. So I want to create a view that will display data in slightly better way:
Id ParentId ParentName Name Desc
--------------------------------------------
1 NULL A
3 1 A A1
4 1 A A2
2 NULL B
5 2 B B1
My problem is getting that ParentName into SELECT query. I obviously (tried) can't do:
SELECT Id, ParentId, (SELECT Name FROM myTable WHERE Id = ParentId) AS ParentName, Name, Desc FROM myTable INNER JOIN .. WHERE ... GROUP BY etc.
Do I have to resort to Common Table Expression (CTE) to get this done ?
Instead of using CTE, You can consider to do that by simple self-join concept:
Select T1.Id, T1.ParentId, ParentTable.Name as ParentName, T1.Name, T1.[Desc]
From tableName T1
Left join tableName ParentTable
on T1.ParentId = ParentTable.Id
order by Name
More reference on Self-Join from Microsoft's TechNet (ref pointer credited to destination-data)
Your example has one parent level only. If there might be deeper nestings you could use a recursive CTE. In this example I added two more elements as children below children:
DECLARE #tbl TABLE(Id INT,ParentId INT, Name VARCHAR(MAX));
INSERT INTO #tbl VALUES
(1,NULL,'A')
,(2,NULL,'B')
,(3,1,'A1')
,(4,1,'A2')
,(5,2,'B1')
,(6,4,'A2a')
,(7,6,'A2a1')
;
WITH RecursiveCTE AS
(
SELECT Id,ParentId,Name,Name AS FullPath
FROM #tbl AS tbl
WHERE ParentId IS NULL
UNION ALL
SELECT a.*
,derived.FullPath + '/' + a.Name
FROM RecursiveCTE AS derived
CROSS APPLY (SELECT Id,ParentId,Name FROM #tbl AS innerTbl WHERE innerTbl.ParentId=derived.Id) AS a
)
SELECT * FROM RecursiveCTE
The result
Id ParentId Name FullPath
1 NULL A A
2 NULL B B
5 2 B1 B/B1
3 1 A1 A/A1
4 1 A2 A/A2
6 4 A2a A/A2/A2a
7 6 A2a1 A/A2/A2a/A2a1
Related
For example: I have a table with these records below
1 A
2 A
3 B
4 C
...
and I need to migrate these record in to another table
1 AA
2 AB
3 B
4 C
...
Meaning if the record is duplicate, it will automatically add one more letter alphabetically.
Just a slightly different approach
Example
Declare #YourTable Table (ID int,[SomeCol] varchar(50))
Insert Into #YourTable Values
(1,'A')
,(2,'A')
,(3,'B')
,(4,'C')
Select *
,NewVal = concat(SomeCol,IIF(sum(1) over (partition by SomeCol)=1,'',char(64+row_number() over ( partition by SomeCol order by ID ))) )
From #YourTable
Returns
ID SomeCol NewVal
1 A AA
2 A AB
3 B B
4 C C
EDIT - Requested UPDATE
Declare #YourTable Table (ID int,[SomeCol] varchar(50))
Insert Into #YourTable Values
(1,'A')
,(2,'A')
,(3,'B')
,(4,'C')
Select *
,NewVal = concat(SomeCol,IIF(sum(1) over (partition by SomeCol)=1,'',replace(char(63+row_number() over ( partition by SomeCol order by ID )),'#','')) )
From #YourTable
Returns
ID SomeCol NewVal
1 A A
2 A AA
3 B B
4 C C
We might be able to handle this requirement with the help of a calendar table mapping secondary letters to duplicate sequence counts:
WITH letters AS (
SELECT 1 AS seq, 'A' AS let UNION ALL
SELECT 2, 'B' UNION ALL
SELECT 3, 'C' UNION ALL
...
SELECT 26, 'Z' UNION ALL
...
),
cte AS (
SELECT id, let, ROW_NUMBER() OVER (PARTITION BY let ORDER BY id) rn,
COUNT(*) OVER (PARTITION BY let) cnt
FROM yourTable
)
SELECT t1.id, t1.let + CASE WHEN t1.cnt > 1 THEN t2.let ELSE '' END AS let
FROM cte t1
LEFT JOIN letters t2
ON t1.id = t2.seq
ORDER BY t1.id;
Demo
How can I delete rows based on just two column conditions.
Example
Table 1
id name phone
1 aa 123
1 aa 345
1 bb 123
2 aa 456
1 NULL 123
1 123
My Expected output
id name phone
1 bb 123
2 aa 456
My condition to delete: if id and name is same, delete the rows
If one of the value in a condition is null or blank it should also delete the row as given in the input.
Delete from table1 t where exists (
Select * from
(Select id, name from table1 group by id, name having count(*) > 1) t2 where t.id = t2.id and t.name = t2.name)
This should do what you want. You can do the select first for testing purposes, then remove the Select and uncomment out the delete.
-- This joins on the table the set of data that has more then 1 row with duplicate IDs, and names. Then you can delete from here.
--DELETE t1
SELECT *
FROM Table1 T1
INNER JOIN (
-- this gets all the records that have more then 1 ID and Name that are the same.
SELECT ID, name
FROM Table1
GROUP BY ID, name
HAVING COUNT(*) > 1
) ToDelete ON T1.ID = ToDelete.ID
AND T1.name = ToDelete.name
create table #tablea (
id int,
name varchar(3),
phone int
)
insert into #tablea (id, name, phone)
values
(1,'aa','123'),
(1,'aa','345'),
(1,'bb','123'),
(2,'aa','456')
select * from #tablea
delete a
from #tablea a
inner join (
select id, name
from #tablea
group by id, name
having COUNT(*) > 1
) b on a.id = b.id and a.name = b.name
select * from #tablea
drop table #tablea
I have two tables A and B, that are in a many to many relationship in a third table. What A want to achieve is get the "repeating" A rows based on B. For example:
table A table B table A_B
---------- ---------- ----------
1 A 1 A
2 B 1 B
3 C 2 A
4 D 2 B
5 3 A
3 B
3 C
4 A
4 D
5 A
What I want is, when searching table A_B by lets say '1', to get only 2, although 3 has both A and B and 4 has A, same goes for 5 too, it matches A but only A so it should be ignored as well. I've tried some suggestions form similar questions with cross join but I had no luck. I am trying to achieve this with just selects and joins, without stored procedures or temporary tables. Any suggestions is welcomed, thank you.
Repeat all base table rows for EACH left join row match
I want my output to look like:
table A_B
----------
2 A
2 B
Or if possible it would be even better if it matches the A_id by which the search is being done
table A_B
----------
1 A
1 B
2 A
2 B
However, the B_id column is not as important so if it is only
table A_B
----------
2
or
table A_B
----------
1
2
is acceptable as well.
EDIT 1:
Until now this is what I've came up with, although a bit unclean but it gets the expected result
select
A_id
from
tableA_B
where
A_id in
(
select
A_id
from
tableA_B
group by
A_id
having
count (A_id) IN (
select
count (A_id)
from
tableA_B
where
A_id = 1
)
)
AND
B_id IN (
select
B_id
from
tableA_B
where
A_id = 1
)
group by
A_id
Basically process of elimination, step by step. It would be ideal if it took only one step.
EDIT 2:
I'm sorry I left out some important information, my B values can be repeated for instance
table A table B table A_B
---------- ---------- ----------
1 A 1 A
2 B 1 B
3 c 2 A
4 D 2 B
5 AB 3 A
6 3 B
3 C
4 A
4 D
5 A
6 AB
so using XML path may return incorrect values. Because in my case it will return 6 as well which is incorrect. I apologies for leaving out this information.
Other solution which use INTERSECT could be:
CREATE TABLE tableA_B (A_id INT, B_id VARCHAR(8))
GO
INSERT INTO tableA_B VALUES
(1,'A'),(1,'B'),(2,'A'),(2,'B'),(3,'A'),(3,'B'),(3,'C'),(4,'A'),(4,'D'),(5,'A')
GO
DECLARE #x INT = 1;
SELECT A_id FROM tableA_B ab1
LEFT JOIN (
SELECT B_id FROM tableA_B
WHERE A_id=#x
) ab2 ON ab1.B_id=ab2.B_id
GROUP BY ab1.A_id
HAVING COUNT(*)=(SELECT COUNT(*) FROM tableA_B WHERE A_id=#x)
INTERSECT
SELECT A_id FROM tableA_B ab1
JOIN (
SELECT B_id FROM tableA_B
WHERE A_id=#x
) ab2 ON ab1.B_id=ab2.B_id
GROUP BY ab1.A_id
HAVING COUNT(*)=(SELECT COUNT(*) FROM tableA_B WHERE A_id=#x)
DROP TABLE tableA_B
GO
Try this,
declare #A_B table(col int,col2 varchar(30))
insert into #A_B VALUES
(1 ,'A') ,(1 ,'B') ,(2 ,'A') ,(2 ,'B') ,(3 ,'A') ,(3 ,'B')
,(3 ,'C') ,(4 ,'A') ,(4 ,'D') ,(5 ,'A'),(6 ,'AB')
declare #i int=1
declare #007 char(1)='-'
;with CTE as
(
select col,col2
,(select #007+col2 from #A_B y
where col=x.col for xml path(''))ConcateCol
from #A_B x
--where col=#i
)
select col,col2
from cte c
where
exists(select * from cte c1
where col=#i and c.ConcateCol=c1.ConcateCol)
you can further maniplate to get whatever desire output
;With tableA(ID)
AS
(
Select 1 uNION ALL
Select 2 uNION ALL
Select 3 uNION ALL
Select 4
)
, tableB(VAL)
As
(
SELECT 'A' UNION ALL
SELECT 'B' UNION ALL
SELECT 'C' UNION ALL
SELECT 'D'
)
SELECT ID,VAL FROM
(
SELECT *,ROW_NUMBER()OVER(PARTITION BY ID ORDER BY ID)AS Seq FROM tableA
CROSS JOIN tableB
)Dt
WHERE ID In (SELECT Id From tableA where id in(1,2) ) AND Dt.Seq<3
OutPut
table A_B
----------
1 A
1 B
2 A
2 B
In a table there are two columns:
-----------
| A | B |
-----------
| 1 | 5 |
| 2 | 1 |
| 3 | 2 |
| 4 | 1 |
-----------
Want a table where if A=B then
-------------------
|Match | notMatch|
-------------------
| 1 | 5 |
| 2 | 3 |
| Null | 4 |
-------------------
How can i do this?
I tried something which shows the Matched part
select distinct C.A as A from Table c inner join Table d on c.A=d.B
Try this:
;WITH TempTable(A, B) AS(
SELECT 1, 5 UNION ALL
SELECT 2, 1 UNION ALL
SELECT 3, 2 UNION ALL
SELECT 4, 1
)
,CTE(Val) AS(
SELECT A FROM TempTable UNION ALL
SELECT B FROM TempTable
)
,Match AS(
SELECT
Rn = ROW_NUMBER() OVER(ORDER BY Val),
Val
FROM CTE c
GROUP BY Val
HAVING COUNT(Val) > 1
)
,NotMatch AS(
SELECT
Rn = ROW_NUMBER() OVER(ORDER BY Val),
Val
FROM CTE c
GROUP BY Val
HAVING COUNT(Val) = 1
)
SELECT
Match = m.Val,
NotMatch= n.Val
FROM Match m
FULL JOIN NotMatch n
ON n.Rn = m.Rn
Try with EXCEPT, MINUS and INTERSECT Statements.
like this:
SELECT A FROM TABLE1 INTERSECT SELECT B FROM TABLE1;
You might want this:
SELECT DISTINCT
C.A as A
FROM
Table c
LEFT OUTER JOIN
Table d
ON
c.A=d.B
WHERE
d.ID IS NULL
Please Note that I use d.ID as an example because I don't see your schema. An alternate is to explicitly state all d.columns IS NULL in WHERE clause.
Your requirement is kind of - let's call it - interesting. Here is a way to solve it using pivot. Personally I would have chosen a different table structure and another way to select data:
Test data:
DECLARE #t table(A TINYINT, B TINYINT)
INSERT #t values
(1,5),(2,1),
(3,2),(4,1)
Query:
;WITH B AS
(
( SELECT A FROM #t
EXCEPT
SELECT B FROM #t)
UNION ALL
( SELECT B FROM #t
EXCEPT
SELECT A FROM #t)
), A AS
(
SELECT A val
FROM #t
INTERSECT
SELECT B
FROM #t
), combine as
(
SELECT val, 'A' col, row_number() over (order by (select 1)) rn FROM A
UNION ALL
SELECT A, 'B' col, row_number() over (order by (select 1)) rn
FROM B
)
SELECT [A], [B]
FROM combine
PIVOT (MAX(val) FOR [col] IN ([A], [B])) AS pvt
Result:
A B
1 3
2 4
NULL 5
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