计算从日期开始的周范围内的结果百分比

Question

我有一个数据表，其中包含以下列显示出勤率。

PupilID、AttendanceDate、AttendanceSession、IsInAttendance（1 或 0）

我需要能够定义开始和结束日期（学期日期）来运行查询，以显示每个学生每周的出勤率。

我可以使用以下代码找到每个学生的总百分比：

SELECT
    PupilID,
    ((SUM(CASE WHEN IsInAttendance = 1 THEN 1 ELSE 0 END) * 100) / COUNT(IsInAttendance))  AS TotalAttPct
FROM #CombinedAttClSe
GROUP BY PupilID

一年中的几个星期使用以下代码：

DECLARE @StartDate DATETIME = '2011-09-01 00:00:00.000';
DECLARE @EndDate DATETIME = '2011-12-31 00:00:00.000';

;WITH GetDates AS
(
    SELECT
        DATEADD(DAY, 0, @startdate) AS TheDate,
        DATEPART(WK, DATEADD(DAY, 1, @startdate)) WkNo,
        DATEPART(YEAR, DATEADD(DAY, 1, @startdate)) DateYear
    UNION ALL
    SELECT
        DATEADD(DAY, 1, TheDate),
        DATEPART(WK, DATEADD(DAY, 1, TheDate)),
        DATEPART(YEAR, DATEADD(DAY, 1, TheDate))
        FROM GetDates
        WHERE TheDate < @enddate
)

SELECT
    WkNo,
    MIN(TheDate) AS SoW,
    MAX(TheDate) AS EoW
FROM GETDATES
GROUP BY WKNO
OPTION (MAXRECURSION 0);

我不确定从哪里开始输出这些数据，如下所示：

学生ID |第 1 周 |第 2 周 |第 3 周 |第 4 周|等

每个“周”标题都包含一个数字以显示出勤率。

编辑：

根据用户的建议，我尝试使用 PIVOT 表和动态 SQL 来解决此问题，但遇到了一些问题。以下是我到目前为止的代码。

CREATE TABLE #yt 
(
  [PupilID] int, 
  [WeekNo] int, 
  [IsInAttendance] int
);

INSERT INTO #yt
(
  [PupilID], 
  [WeekNo],
  [IsInAttendance]
)
VALUES
    (102, 1, 1),
    (102, 1, 1),
    (102, 1, 1),
    (102, 1, 1),
    (102, 1, 0),
    (102, 1, 1),
    (102, 1, 0),
    (102, 1, 1),
    (102, 2, 1),
    (102, 2, 1),
    (102, 2, 1),
    (102, 2, 1),
    (102, 2, 1),
    (102, 2, 1),
    (102, 2, 0),
    (102, 2, 1),
    (101, 1, 1),
    (101, 1, 1),
    (101, 1, 1),
    (101, 1, 1),
    (101, 1, 1),
    (101, 1, 1),
    (101, 1, 1),
    (101, 2, 1),
    (101, 2, 1),
    (101, 2, 1),
    (101, 2, 1),
    (101, 2, 0)

DECLARE @WkCols AS NVARCHAR(MAX),
        @WkQuery AS NVARCHAR(MAX)

select @WkCols = STUFF((SELECT ',' + QUOTENAME(WeekNo) 
                    FROM #yt
                    GROUP BY WeekNo
                    ORDER BY WeekNo
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @WkQuery = 'SELECT PupilID,' + @WkCols + ' FROM 
            (
                SELECT PupilID, WeekNo, IsInAttendance
                FROM #yt
            ) x
            PIVOT 
            (
                SUM(CASE WHEN IsInAttendance = 1 THEN 1 ELSE 0 END) * 100 / COUNT(IsInAttendance) 
                FOR WeekNo IN (' + @WkCols + ')
            ) p '

execute(@WkQuery);

目前我收到错误“关键字“CASE”附近的语法不正确。”

任何指针或帮助将不胜感激。

Answer 1

很遗憾，您不能在 PIVOT 聚合函数上应用复杂的聚合。因此，您将不得不使用简单的SUM 或MAX。尝试在旋转之前计算出勤率：

SELECT
    T.PupilID,
    T.WeekNo,
    AttendancePercentage = SUM(T.IsInAttendance) * 100.0 / COUNT(1)
FROM
    #yt AS T
GROUP BY
    T.PupilID,
    T.WeekNo

还有支点：

DECLARE @WkCols AS NVARCHAR(MAX),
        @WkQuery AS NVARCHAR(MAX)

select @WkCols = STUFF((SELECT ',' + QUOTENAME(WeekNo) 
                    FROM #yt
                    GROUP BY WeekNo
                    ORDER BY WeekNo
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @WkQuery = 'SELECT PupilID,' + @WkCols + ' FROM 
            (
                SELECT
                    T.PupilID,
                    T.WeekNo,
                    AttendancePercentage = SUM(T.IsInAttendance) * 100.0 / COUNT(1)
                FROM
                    #yt AS T
                GROUP BY
                    T.PupilID,
                    T.WeekNo
            ) x
            PIVOT 
            (
                MAX(AttendancePercentage) 
                FOR WeekNo IN (' + @WkCols + ')
            ) p '

execute(@WkQuery);