在SQL中找到連續值

Question

我想找出每個模塊的每個學生的連續缺失， 這裏是我的原始結果。

，我想我的輸出是增加一個連續缺席列，並找出連續缺席了每個學生模塊。

Answer 1

嘗試這樣的。

DECLARE @Tbl TABLE 
(
    [Id] [int] IDENTITY(1,1), 
    [Studentcode] VARCHAR(50), 
    [Semester] VARCHAR(50), 
    [ModuleCode] VARCHAR(50), 
    [Date] VARCHAR(50), 
    [WkNo] VARCHAR(50), 
    [Attended] VARCHAR(50), 
    [Absent] [int] 
) 

INSERT INTO @Tbl 
SELECT [Studentcode] 
     ,[Semester] 
     ,[ModuleCode] 
     ,[Date] 
     ,[WkNo] 
     ,[Attended] 
     ,[Absent] FROM Attendance 
ORDER BY studentcode,modulecode,date 

SELECT T1.*, CASE WHEN (T1.Absent = 1 AND T2.Absent = 1) 
         AND (T1.ModuleCode = T2.ModuleCode) 
      THEN 1 ELSE 0 END AS CosecutiveAbsence 
FROM @Tbl T1 
LEFT OUTER JOIN @Tbl T2 
ON T1.Id = T2.Id + 1