SQL Server中如何将列转换为行

我有一张这样的考勤表：

Student_id   attendance_date    status
-----------  ----------------   ---------
       1     1/8/2014          Present
       2     1/8/2015          Absent
       1     2/8/2014          Present
       2     2/8/2015          Present
       1     3/8/2014          Present
       2     3/8/2015          Present

预期产出如下：

  Student_ id   1/8/2014      2/8/2014     3/8/2014
 -------------  ---------     ---------   ----------
         1     present         present      present
         2     absent          present      present

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请帮助我获得预期的输出…

您需要创建一个过程，并使用Dynamic Pivot进行如下操作

DECLARE @dates NVARCHAR(MAX)
DECLARE @query AS NVARCHAR(MAX)

--Get all the dates to pivot
SELECT @dates = ISNULL(@dates  + ',','') 
       + QUOTENAME(attendance_date)
FROM (SELECT DISTINCT attendance_date FROM attendance) AS attendance 

--Construct the dynamic pivot query

SET @query = 
  N'SELECT status, ' + @dates + '
    FROM attendance
    PIVOT(MAX(status) 
          FOR dates IN (' + @dates + ')) AS pivotTable'

-- excecute the dynamic query

EXEC sp_executesql @query

这可能有用吗

SELECT   t.[user_id], t.[attendance_date],t.[status] 
     FROM    Attendance t 
 PIVOT   ( MIN(status) 
      FOR attendance_date IN ([1/8/2014],[2/8/2014],[3/8/2014]) ) pvt;

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您正在寻找数据透视图。您还需要格式化日期字符串，尤其是。。。这里将日期或日期时间值与字符串进行比较。并在设置@dates和@query值的查询中包含一个日期范围筛选器。我收到以下错误：-“PIVOT”附近的语法不正确。您可能需要将当前数据库的兼容性级别设置为更高的值才能启用此功能。有关ALTER DATABASE的“设置兼容性”级别选项，请参阅帮助。