Sql server 如何查询sql中的最新记录日期值
我有以下结构Sql server 如何查询sql中的最新记录日期值,sql-server,tsql,pivot,Sql Server,Tsql,Pivot,我有以下结构 username, date, value, IDexam, No.Points -------------------------- brad, 1/2/2010, not pass exam1 10 brad, 2/2/2010, pass exam1 15 brad, 1/3/2010, pass exam2 20 brad, 1/3/2010,
username, date, value, IDexam, No.Points
--------------------------
brad, 1/2/2010, not pass exam1 10
brad, 2/2/2010, pass exam1 15
brad, 1/3/2010, pass exam2 20
brad, 1/3/2010, not pass exam3 12
fred, 1/3/2010, pass exam2 25
fred, 5/3/2010, pass exam2 20
fred, 5/4/2010, not pass exam3 12
etc..
我想要的是:
username, Exam1-value, Exam1-date, Exam1-points, Exam2-value, Exam2-date, Exam2-points, Exam3-value, Exam3-date, Exam3-points
--------------------------
brad, pass, 2/2/2010 15, pass, 1/3/2010, 20, , ,
fred, , , , pass, 5/3/2010 20, not pass, 5/4/2010, 12
因此,对于同一IDExam的多个记录,可以为同一用户获取la最新记录,但在列上
提前感谢试试这个:
CREATE TABLE #DataSource
(
[username] VARCHAR(16)
,[date] DATE
,[value] VARCHAR(16)
,[IDexam] VARCHAR(16)
,[No.Points] TINYINT
);
INSERT INTO #DataSource ([username], [date], [value], [IDexam], [No.Points])
VALUES ('brad', '1/2/2010', 'not pass', 'exam1', 10)
,('brad', '2/2/2010', 'pass', 'exam1', 15)
,('brad', '1/3/2010', 'pass', 'exam2', 20)
,('brad', '1/3/2010', 'not pass', 'exam3', 12)
,('fred', '1/3/2010', 'pass', 'exam2', 25)
,('fred', '5/3/2010', 'pass', 'exam2', 20)
,('fred', '5/4/2010', 'not pass', 'exam3', 12);
SELECT [username]
,MAX(IIF([IDexam] = 'exam1', [date], NULL)) AS [Exam1-value]
,MAX(IIF([IDexam] = 'exam1', [value], NULL)) AS [Exam1-date]
,MAX(IIF([IDexam] = 'exam1', [No.Points], NULL)) AS [Exam1-points]
,MAX(IIF([IDexam] = 'exam2', [date], NULL)) AS [Exam2-value]
,MAX(IIF([IDexam] = 'exam2', [value], NULL)) AS [Exam2-date]
,MAX(IIF([IDexam] = 'exam2', [No.Points], NULL)) AS [Exam2-points]
,MAX(IIF([IDexam] = 'exam3', [date], NULL)) AS [Exam3-value]
,MAX(IIF([IDexam] = 'exam3', [value], NULL)) AS [Exam3-date]
,MAX(IIF([IDexam] = 'exam3', [No.Points], NULL)) AS [Exam3-points]
,MAX(IIF([IDexam] = 'exam4', [date], NULL)) AS [Exam4-value]
,MAX(IIF([IDexam] = 'exam4', [value], NULL)) AS [Exam4-date]
,MAX(IIF([IDexam] = 'exam4', [No.Points], NULL)) AS [Exam4-points]
,MAX(IIF([IDexam] = 'exam5', [date], NULL)) AS [Exam5-value]
,MAX(IIF([IDexam] = 'exam5', [value], NULL)) AS [Exam5-date]
,MAX(IIF([IDexam] = 'exam5', [No.Points], NULL)) AS [Exam5-points]
FROM
(
SELECT *
,ROW_NUMBER() OVER (PARTITION BY [username], [IDexam] ORDER BY [date] DESC) AS [RowID]
FROM #DataSource
) DS
WHERE [RowID] = 1
GROUP BY [username]
DROP TABLE #DataSource;
IDexam列表是否已修复?是的,检查已修复(exam1到exam5)。如果用户没有任何检查,则记录必须类似于user1 null、null null等。max的问题是,所有3列值可能来自不同的行。假设你有一个用户,参加了3次考试,1/2没有通过10分;12/2通过60pt;在16/2通过54点。获得的结果将是16/2通过60pt,这是不正确的。首先,您必须使用带窗口的行号标识最后一个条目的行。之后,您可以使用max脚本