T-SQL, Select first row of a set
I have a table that is setup like so:
ID int
Hash varchar
OtherID int
Some Example data:
1 3pm6Qav1Vd 23
2 3pm6Qav1Vd 2
3 3pm6Qav1Vd 19
4 3pm6Qav1Vd 17
5 RSUBe2VBtl 2
6 3pm6Qav1Vd 4
7 3pm6Qav1Vd 21
8 RSUBe2VBtl 23
9 RSUBe2VBtl 19
I would like to be able to pull out just the first row of each hash set:
1 3pm6Qav1Vd 23
5 RSUBe2VBtl 2
The rows would each be the lowest ID for each Hash. 开发者_StackOverflow中文版I'm using T-SQL on SQL Server 2005. I'm not really sure where to begin on this one.
SELECT t.ID, t.Hash, t.OtherID
FROM (SELECT ID, Hash, OtherID, ROW_NUMBER() OVER(PARTITION BY Hash ORDER BY ID) AS RowNum
FROM YourTable) t
WHERE t.RowNum = 1
select ID, Hash, OtherId
from (
select ID, Hash, OtherId, row_number() over (partition by Hash order by ID) as RN
from yourtable
) a
where RN = 1
Simple!
SELECT *
FROM [tableName]
WHERE ID IN (
SELECT MIN(ID)
FROM [tableName]
GROUP BY Hash
)
Hope this helps.
Do something like below
SELECT * FROM Table T1
INNER JOIN (
SELECT MIN(ID) ID FROM Table GROUP BY Hash) T2
ON T1. ID = T2.ID
Hope this helps!!
精彩评论