From Table
Name GroupID
a Null
b 1
c 1
d 2
e Null
f Null
g 3
Result expected from random top 4 selection
Name GruopID
a Null
b 1
e Null
g 3
Resuming I want to get random names but only 1 kind of groupid if groupid is <> null
The select Newid() type returns
"Select Top(4) * FROM Table Order By NEWID()"
Name GruopID
a Null
b 1
e Null
c 1
I don´t want that. Hope i made my self clear!
Thanks in advance
You can try this (on SQL Server 2005+).
;WITH CTE AS
(
SELECT *, ROW_NUMBER() OVER(PARTITION BY GroupId ORDER BY NEWID()) Corr
FROM YourTable
)
SELECT TOP 4 Name, GroupId
FROM CTE
WHERE GroupId IS NULL OR Corr = 1
ORDER BY NEWID()
Related
Following scenario, in which I need top 3 records from the same table with specific condition and need to merge with second query records with excluding first query result.
Table A:
Id Name Flag
-------------
1 A 1
2 B 0
3 C 0
4 D 1
5 E 0
6 F 1
7 G 0
8 H 0
Top 3 where flag = 1 with latest records page index 1 and row count 5
Id Name Flag
----------------
6 F 1
4 D 1 first require flag =1 first 3 records
1 A 1
---------------------------------------
8 H 0
7 G 0
Page index 2 and row count 5 with latest records
Id Name Flag
--------------
6 F 1
5 E 0
3 C 0
2 B 0
How can I achieve this with a SQL query?
IF (#PageNumber = 0)
BEGIN
SELECT TOP (#RowsPerPage) [Id], [Name], [Flag]
FROM
(SELECT [Id], [Name], [Flag]
FROM
(SELECT TOP 3 [Id], [Name], [Flag]
FROM [A]
WHERE Flag = 1
ORDER BY Id DESC
UNION
SELECT [Id], [Name], [Flag]
FROM [A]
ORDER BY Id DESC) T
END
ELSE
BEGIN
// Normal paging query excluding top 3 flag records.
END
Try this
WITH CTE
AS
(
SELECT
Seq1 = ROW_NUMBER() OVER(PARTITION BY Flag ORDER BY Id DESC),
Seq2 = ROW_NUMBER() OVER(ORDER BY Id DESC),
Id,
Name,
Flag
FROM t1
)
SELECT
Seq1,
id,
name,
flag
FROM CTE
WHERE Seq1 < 4
UNION ALL
SELECT
Seq2,
id,
name,
flag
FROM CTE
WHERE Seq1 >3
ORDER BY 4 desc,1
suppose i have a data like that
ID ParentID Name
1 null a
2 1 b
3 2 c
4 1 d
5 4 e
if i use cte(common table expression) provided by sql it shows me result like this
ID ParentID Name
1 null a
2 1 b
4 1 d
3 2 c
5 4 e
but i want to arrange data like, query should complete first node till end , then move to other node . like
ID ParentID Name
1 null a
2 1 b
3 2 c
4 1 d
5 4 e
Note: i have a primary key with datatype :uniqueidentifier so i cannot use order by clause after CTE
Example
Declare #Top int = null --<< Sets top of Hier Try 2
;with cteP as (
Select ID
,ParentID
,Name
,Path = cast('/'+[ID]+'/' as varchar(500))
From YourTable
Where IsNull(#Top,-1) = case when #Top is null then isnull(ParentID ,-1) else ID end
Union All
Select r.ID
,r.ParentID
,r.Name
,cast(p.path + '/'+r.[ID]+'/' as varchar(500))
From YourTable r
Join cteP p on r.ParentID = p.ID)
Select ID
,ParentID
,Name
From cteP A
Order By Path
Returns
Without seeing your query, I think you can do something like this:
WITH CTE_Example
AS
(
YOUR QUERY
)
SELECT *
FROM CTE_Example
ORDER BY ID
I need to make a query where only the last line of each user that has a car gets a license plate number.
ID UserId LicensePlate HasCar
1 1 ABC123 1
2 1 ABC123 1
3 2 NULL 0
4 3 UVW789 1
5 3 UVW789 1
Should become:
ID UserId LicensePlate HasCar
1 1 NULL 1
2 1 ABC123 1
3 2 NULL 0
4 3 NULL 1
5 3 UVW789 1
So I basically need to find all users with a licenseplate and change all but the last one and make the LicensePlate NULL
Assuming the ID column is an identity column so it can provide the ordering, something like this should do the trick:
;WITH CTE AS
(
SELECT Id,
UserId,
LicensePlate,
ROW_NUMBER() OVER(PARTITION BY UserId ORDER BY Id DESC) rn
FROM Table
WHERE HasCar = 1
)
UPDATE CTE
SET LicensePlate = NULL
WHERE rn > 1
You can try this
UPDATE l
SET l.LicensePlate = null
FROM Car l
INNER JOIN (SELECT UserId, Max(Id) AS max_id
FROM Car
GROUP BY UserId) m ON m.UserId = l.UserId
AND m.max_id <> l.id
You can do it with a join on the table itself like that :
UPDATE car c
INNER JOIN car c2 ON c.userId = c2.userId AND c.id < c2.id AND c.HasCar = 1 AND c2.HasCar = 1
SET c.LicensePlate = NULL
The condition c.id < c2.id will avoid to select the last line
By using LAG Function also you can achieve it.
;WITH License(ID,UserId,LicensePlate,HasCar)
as
(
SELECT 1,1,'ABC123',1 UNION ALL
SELECT 2,1,'ABC123',1 UNION ALL
SELECT 3,2,NULL ,0 UNION ALL
SELECT 4,3,'UVW789',1 UNION ALL
SELECT 5,3,'UVW789',1
)
SELECT ID,UserId,LAG(LicensePlate,1,NULL) OVER(PARTITION BY UserId ORDER BY LicensePlate),HasCar FROM License
If I have a table like this:
Id StateId Name
1 1 a
2 2 b
3 1 c
4 1 d
5 3 e
6 2 f
I want to select like below:
Id StateId Name
4 1 d
5 3 e
6 2 f
For example, Ids 1,3,4 have stateid 1. So select row with max Id, i.e, 4.
; WITH CTE AS
(
SELECT *, ROW_NUMBER() OVER(PARTITION BY STATEID ORDER BY ID DESC) AS RN
)SELECT ID, STATEID, NAME FROM CTE WHERE RN = 1
You can use ROW_NUMBER() + TOP 1 WITH TIES:
SELECT TOP 1 WITH TIES
Id,
StateId,
[Name]
FROM YourTable
ORDER BY ROW_NUMBER() OVER (PARTITION BY StateId ORDER BY Id DESC)
Output:
Id StateId Name
4 1 d
6 2 f
5 3 e
Disclaimer: I gave this answer before the OP had specified an actual database, and hence avoided using window functions. For a possibly more appropriate answer, see the reply by #Tanjim above.
Here is an option using joins which should work across most RDBMS.
SELECT t1.*
FROM yourTable t1
INNER JOIN
(
SELECT StateId, MAX(Id) AS Id
FROM yourTable
GROUP BY StateId
) t2
ON t1.StateId = t2.StateId AND
t1.Id = t2.Id
The following using a subquery, to find the maximum Id for each of the states. The WHERE clause then only includes rows with ids from that subquery.
SELECT
[Id], [StateID], [Name]
FROM
TABLENAME S1
WHERE
Id IN (SELECT MAX(Id) FROM TABLENAME S2 WHERE S2.StateID = S1.StateID)
I have the following table:
Name Field
A 1
B 1
C 1
D 1
E 1
F 1
G 1
H 2
I 2
J 2
K 3
L 3
M 3
N 3
O 3
P 3
Q 3
R 3
S 3
T 3
I need a SQL query which will generate me a set with 5 random rows for each distinct value on column Field.
For example, results expected:
Name Field
A 1
B 1
D 1
E 1
G 1
J 2
I 2
H 2
M 3
Q 3
T 3
S 3
P 3
Is there an easy way to do this? Or should i split that table into more tables and generate random for each table then union them?
You can do this with a CTE using a ROW_NUMBER() whilst PARTITIONing on the Field:
;With Cte As
(
Select Name, Field,
Row_Number() Over (Partition By Field Order By NewId()) RN
From YourTable
)
Select Name, Field
From Cte
Where RN <= 5
SQL Fiddle
You can readily do this with row_number():
select name, field
from (select t.*,
row_number() over (partition by field order by newid()) as seqnum
from t
) t
where seqnum <= 5;
An enhancement to Gordon Linoff's code, This code really helped me if you need criteria in your query.
select *
from (select t.*,
row_number() over (partition by region order by newid()) as seqnum
from MyTable t
WHERE t.program = 'ACME'
) t
where seqnum <= 1500;