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)
Related
Can't see the wood for the trees on this and I'm sure it's simple.
I'm trying to return the max ID for a related record in a joined table
Table1
NiD
Name
1
Peter
2
John
3
Arthur
Table2
ID
NiD
Value
1
1
5
2
2
10
3
3
10
4
1
20
5
2
15
Max Results
NiD
ID
Value
1
4
20
2
5
15
3
3
10
You can use row_number() for this:
select NiD, ID, Value
from (select t2.*,
row_number() over (partition by NiD order by ID desc) as seqnum
from table2 t2
) t2
where seqnum = 1;
As the question is stated, you do not need table1, because table2 has all the ids.
This is how I'd do it, I think ID and Value will be NULL when Table2 does not have a corresponding entry for a Table1 record:
SELECT NiD, ID, [Value]
FROM Table1
OUTER APPLY (
SELECT TOP 1 ID, [Value]
FROM Table2
WHERE Table1.NiD = Table2.NiD
ORDER BY [Value] DESC
) AS Top_Table2
CREATE TABLE Names
(
NID INT,
[Name] VARCHAR(MAX)
)
CREATE TABLE Results
(
ID INT,
NID INT,
VALUE INT
)
INSERT INTO Names VALUES (1,'Peter'),(2,'John'),(3,'Arthur')
INSERT INTO Results VALUES (1,1,5),(2,2,10),(3,3,10),(4,1,20),(5,2,15)
SELECT a.NID,
r.ID,
a.MaxVal
FROM (
SELECT NID,
MAX(VALUE) as MaxVal
FROM Results r
GROUP BY NID
) a
JOIN Results r
ON a.NID = r.NID AND a.MaxVal = r.VALUE
ORDER BY NID
Here's what I have used in similar situations, performance was fine, provided that the data set wasn't too large (under 1M rows).
SELECT
table1.nid
,table2.id
,table2.value
FROM table1
INNER JOIN table2 ON table1.nid = table2.nid
WHERE table2.value = (
SELECT MAX(value)
FROM table2
WHERE nid = table1.nid)
ORDER BY 1
I need to select data base upon three conditions
Find the latest date (StorageDate Column) from the table for each record
See if there is more then one entry for date (StorageDate Column) found in first step for same ID (ID Column)
and then see if DuplicateID is = 2
So if table has following data:
ID |StorageDate | DuplicateTypeID
1 |2014-10-22 | 1
1 |2014-10-22 | 2
1 |2014-10-18 | 1
2 |2014-10-12 | 1
3 |2014-10-11 | 1
4 |2014-09-02 | 1
4 |2014-09-02 | 2
Then I should get following results
ID
1
4
I have written following query but it is really slow, I was wondering if anyone has better way to write it.
SELECT DISTINCT(TD.RecordID)
FROM dbo.MyTable TD
JOIN (
SELECT T1.RecordID, T2.MaxDate,COUNT(*) AS RecordCount
FROM MyTable T1 WITH (nolock)
JOIN (
SELECT RecordID, MAX(StorageDate) AS MaxDate
FROM MyTable WITH (nolock)
GROUP BY RecordID)T2
ON T1.RecordID = T2.RecordID AND T1.StorageDate = T2.MaxDate
GROUP BY T1.RecordID, T2.MaxDate
HAVING COUNT(*) > 1
)PT ON TD.RecordID = PT.RecordID AND TD.StorageDate = PT.MaxDate
WHERE TD.DuplicateTypeID = 2
Try this and see how the performance goes:
;WITH
tmp AS
(
SELECT *,
RANK() OVER (PARTITION BY ID ORDER BY StorageDate DESC) AS StorageDateRank,
COUNT(ID) OVER (PARTITION BY ID, StorageDate) AS StorageDateCount
FROM MyTable
)
SELECT DISTINCT ID
FROM tmp
WHERE StorageDateRank = 1 -- latest date for each ID
AND StorageDateCount > 1 -- more than 1 entry for date
AND DuplicateTypeID = 2 -- DuplicateTypeID = 2
You can use analytic function rank , can you try this query ?
Select recordId from
(
select *, rank() over ( partition by recordId order by [StorageDate] desc) as rn
from mytable
) T
where rn =1
group by recordId
having count(*) >1
and sum( case when duplicatetypeid =2 then 1 else 0 end) >=1
I have a table_1:
id custno
1 1
2 2
3 3
and a table_2:
id custno qty descr
1 1 10 a
2 1 7 b
3 2 4 c
4 3 7 d
5 1 5 e
6 1 5 f
When I run this query to show the minimum order quantities from every customer:
SELECT DISTINCT table_1.custno,table_2.qty,table_2.descr
FROM table_1
LEFT OUTER JOIN table_2
ON table_1.custno = table_2.custno AND qty = (SELECT MIN(qty) FROM table_2
WHERE table_2.custno = table_1.custno )
Then I get this result:
custno qty descr
1 5 e
1 5 f
2 4 c
3 7 d
Customer 1 appears twice each time with the same minimum qty (& a different description) but I only want to see customer 1 appear once. I don't care if that is the record with 'e' as a description or 'f' as a description.
First of all... I'm not sure why you need to include table_1 in the queries to begin with:
select custno, min(qty) as min_qty
from table_2
group by custno;
But just in case there is other information that you need that wasn't included in the question:
select table_1.custno, ifnull(min(qty),0) as min_qty
from table_1
left outer join table_2
on table_1.custno = table_2.custno
group by table_1.custno;
"Generic" SQL way:
SELECT table_1.custno,table_2.qty,table_2.descr
FROM table_1, table_2
WHERE table_2.id = (SELECT TOP 1 id
FROM table_2
WHERE custno = table_1.custno
ORDER BY qty )
SQL 2008 way (probably faster):
SELECT custno, qty, descr
FROM
(SELECT
custno,
qty,
descr,
ROW_NUMBER() OVER (PARTITION BY custno ORDER BY qty) RowNum
FROM table_2
) A
WHERE RowNum = 1
If you use SQL-Server you could use ROW_NUMBER and a CTE:
WITH CTE AS
(
SELECT table_1.custno,table_2.qty,table_2.descr,
RN = ROW_NUMBER() OVER ( PARTITION BY table_1.custno
Order By table_2.qty ASC)
FROM table_1
LEFT OUTER JOIN table_2
ON table_1.custno = table_2.custno
)
SELECT custno, qty,descr
FROM CTE
WHERE RN = 1
Demolink
Say I have a table that looks like this:
Person Table
ID AccountID Name
1 6 Billy
2 6 Joe
3 6 Tom
4 8 Jamie
5 8 Jake
6 8 Sam
I have two queries that I know work by themselves:
Select Name Group1 from person where accountid = 6
Select Name Group2 from person where accountid = 8
But I want a single Result Set to look like this:
Group1 Group2
Billy Jamie
Joe Jake
Tom Same
You can use row_number() to assign a distinct value for each row, ans then use a FULL OUTER JOIN to join the two subqueries:
select t1.group1,
t2.group2
from
(
select name group1,
row_number() over(order by id) rn
from yourtable
where accountid = 6
) t1
full outer join
(
select name group2,
row_number() over(order by id) rn
from yourtable
where accountid = 8
) t2
on t1.rn = t2.rn;
See SQL Fiddle with Demo
I agree you should do this client side. But it can be done in T/SQL:
select G1.Name as Group1
, G2.Name as Group2
from (
select row_number() over (order by ID) as rn
, *
from Group
where AccountID = 6
) as G1
full outer join
(
select row_number() over (order by ID) as rn
, *
from Group
where AccountID = 8
) as G2
on G1.rn = G2.rn
order by
coalesce(G1.rn, G2.rn)
table1 & table2:
table1 & table2 http://aftabfarda.parsfile.com/1.png
SELECT *
FROM (SELECT DISTINCT dbo.tb1.ID, dbo.tb1.name, ROW_NUMBER() OVER (ORDER BY tb1.id DESC) AS row
FROM dbo.tb1 INNER JOIN
dbo.tb2 ON dbo.tb1.ID = dbo.tb2.id_tb1) AS a
WHERE row BETWEEN 1 AND 7
ORDER BY id DESC
Result:
Result... http://aftabfarda.parsfile.com/3.png
(id 11 Repeated 3 times)
How can I have this output:
ID name row
-- ------ ---
11 user11 1
10 user10 2
9 user9 3
8 user8 4
7 user7 5
6 user6 6
5 user5 7
You could apply distinct before row_number using a subquery:
select *
from (
select row_number() over (order by tbl.id desc) as row
, *
from (
select distinct t1.ID
, tb1.name
from dbo.tb1 as t1
join dbo.tb2 as t2
on t1.ID = t2.id_tb1
) as sub_dist
) as sub_with_rn
where row between 1 and 7
Alternatively to #Andomar's suggestion, you could use DENSE_RANK instead of ROW_NUMBER and rank the rows first (in the subquery), then apply DISTINCT (in the outer query):
SELECT DISTINCT
ID,
name,
row
FROM (
SELECT
t1.ID,
t1.name,
DENSE_RANK() OVER (ORDER BY t1.ID DESC) AS row
FROM dbo.tb1 t1
INNER JOIN dbo.tb2 t2 ON t1.ID = t2.id_tb1
) AS a
WHERE row BETWEEN 1 AND 7
ORDER BY ID DESC
Similar, but not quite the same, although both might boil down to the same query plan, I'm just not sure. Worth testing, I think.
And, of course, you could also try a semi-join instead of a proper join, in the form of either IN or EXISTS, to prevent duplicates in the first place:
SELECT
ID,
name,
row
FROM (
SELECT
ID,
name,
ROW_NUMBER() OVER (ORDER BY ID DESC) AS row
FROM dbo.tb1
WHERE ID IN (SELECT id_tb1 FROM dbo.tb2)
/* Or:
WHERE EXISTS (
SELECT *
FROM dbo.tb2
WHERE id_tb1 = dbo.tb1.ID
)
*/
) AS a
WHERE row BETWEEN 1 AND 7
ORDER BY ID DESC