请考虑下表...
DECLARE @tmp TABLE
(
ID int,
userID int,
testID int,
someDate datetime
)
...包含以下值:
INSERT INTO @tmp (ID, userID, testID, someDate) VALUES (1, 1, 50, '2010-10-01')
INSERT INTO @tmp (ID, userID, testID, someDate) VALUES (2, 1, 50, '2010-11-01')
INSERT INTO @tmp (ID, userID, testID, someDate) VALUES (3, 1, 50, '2010-12-01')
INSERT INTO @tmp (ID, userID, testID, someDate) VALUES (4, 2, 20, '2010-10-01')
INSERT INTO @tmp (ID, userID, testID, someDate) VALUES (5, 2, 30, '2010-11-01')
INSERT INTO @tmp (ID, userID, testID, someDate) VALUES (6, 2, 20, '2012-11-01')
我需要检索每个 userID/testID 值组合的最大日期,以及随附的 ID 值。结果应该是:
ID userID testID someDate
-------------------------------
3 1 50 2010-12-01
5 2 30 2010-11-01
6 2 20 2012-11-01
当我尝试以下查询时,结果集变得不正确并且显示了所有行。我不能从 GROUP BY 子句中省略 ID,因为它会导致错误。有人可以帮忙吗?将表连接到自身以获取这些值似乎很啰嗦。
SELECT ID, userID, testID, MAX(someDate)
FROM @tmp
GROUP BY testId,userID,ID;
最佳答案
请尝试:
select * from (
select
*,
ROW_NUMBER() over (partition by userID, testID order by SomeDate desc) Rnum
From @tmp
)x where Rnum=1
关于sql - 选择 MAX 日期加上 ID 值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/17424333/