我正在尝试执行此查询。这就是我所拥有的。
我的表是:表
StudyID FacultyID Year Access1 Access2 Access3
1 1 2014 4 8 5
1 2 2014 8 4 7
1 1 2013 5 4 4
2 3 2014 4 6 5
2 5 2013 5 8 10
2 4 2014 5 5 7
3 7 2013 9 4 7
我希望按StudyID和Year分组并获取每个字段Access1 Access2和Access3的最小值,并仅显示去年,我的意思是每个组的第一行。 这是结果。
StudyID Year Access1 Access2 Access3
1 2014 4 4 5
2 2014 4 5 5
3 2013 9 4 7
这是我的查询:
SELECT DISTINCT T.StudyID, T.Year, MIN(T.Access1), MIN(T.Access2), MIN(T.Access3)
FROM T
GROUP BY T.StudyID, T.Year
ORDER BY T.StudyID, T.Year DESC
我也试过这个。
;WITH MyQuery AS ( SELECT DISTINCT T.StudyID, T.Year, MIN(T.Access1), MIN(T.Access2), MIN(T.Access3),ROW_NUMBER() OVER (PARTITION BY T.StudyID, T.Year ORDER BY T.StudyID, T.Year DESC) AS rownumber
FROM T GROUP BY T.StudyID, T.Year ORDER BY T.StudyID , T.Year DESC ) SELECT * FROM MyQuery WHERE rownumber = 1
任何成功,我知道我错过了什么......但不知道是什么? 在此先感谢!!!!
答案 0 :(得分:7)
您可以GROUP BY StudyID, Year
然后在外部查询中选择每个StudyID, Year
组中的第一行:
SELECT StudyID, Year, minAccess1, minAccess2, minAccess3
FROM (
SELECT StudyID, Year, min(Access1) minAccess1, min(Access2) minAccess2,
min(Access3) minAccess3,
ROW_NUMBER() OVER (PARTITION BY StudyID ORDER BY Year DESC) AS rn
FROM mytable
GROUP BY StudyID, Year ) t
WHERE t.rn = 1
ROW_NUMBER
用于根据StudyID
值为每个Year
组分配订购号。具有最大Year
值的行被指定为rn = 1
。
答案 1 :(得分:0)
试试这个:
SELECT DISTINCT T.StudyID, T.Year, MIN(T.Access1), MIN(T.Access2), MIN(T.Access3)
FROM myTable T
WHERE T.Year = (SELECT MAX(T2.Year) FROM myTable T2 WHERE T2.StudyID = T.StudyID)
GROUP BY T.StudyID
它在SQLite中提供了你想要的结果,但也许在SQL-Server中需要一些我不确定的别名。现在无法测试。
答案 2 :(得分:0)
这是你想要的答案
SELECT DISTINCT T.StudyID, T.Year, MIN(T.Access1) as Access1, MIN(T.Access2) as Access2, MIN(T.Access3) as Access3
FROM T T
WHERE T.Year = (SELECT MAX(T2.Year) FROM T T2 WHERE StudyID = T.StudyID)
GROUP BY T.StudyID, T.Year
Order by 1