SQL 确定缺勤是否为“辍学”

Question

我每周出勤 table，每周出勤 "Present" 或 "Absent"

需要修改如下并附上理由：

如果一个人整整一个月都没有出席，他将更改为 "DROPOUT" 数周 he/she 在该月之前缺席，直到他重新出席。

我已经尝试使用 SQL 检查 "Streaks" 检查合并出勤的月份，但无法使 "Dropped out from" 正确。任何帮助将不胜感激。

使用 Sample SourceData having 1 as "Absent" & 0 as "Present" ，我使用了以下 SQL 但有一些错误

/* Calculate RunGroup */
SELECT WeekNum, Abs_Status, (SELECT COUNT(*) FROM [SourceData] G WHERE G.Abs_Status <> GR.Abs_Status AND G.WeekNum <= GR.WeekNum) as RunGroup 
INTO [RunGroup]
FROM [SourceData] GR;
GO

/* Determine how many weeks in each run */
SELECT Abs_Status, MIN(WeekNum) as StartDate, MAX(WeekNum) as EndDate, COUNT(*) as Games 
INTO [WeeksinRun]
FROM [RunGroup] A GROUP BY Abs_Status, RunGroup ORDER BY Min(WeekNum);
GO


/****** What to mark as Dropouts  ******/
SELECT [StartDate]
      ,[EndDate]
  INTO [WeekstoUpd]
  FROM [WeeksinRun] a,[SourceData] b, [SourceData] c
  where a.[StartDate] = b.[Weeknum]
  and a.[EndDate] = c.[Weeknum]
  and b.[MONTH] <> c.[MONTH]
  and a.Abs_Status = '1'
  and a.[StartDate] <> '2013 Week 01';
GO

/****** Update Dropout Weeks  ******/
update [SourceData]
set [SourceData].[Abs_Status] = '-2'
  FROM [SourceData],[WeekstoUpd]
  where [WeekNum]>=[StartDate] and [WeekNum]<=[EndDate];
GO

/****** Update Absent Weeks  ******/
UPDATE [SourceData]
SET    [Abs_Status] = '-1'
FROM   [SourceData]
WHERE  [SourceData].[Abs_Status] = '1';
GO

SQL Fiddle Code

Answer 1

不确定我是否理解正确，但也许这就是您想要的：

update s 
set s.Abs_Status = 2
from SourceData S
where not exists (
  select 1 from SourceData S2
  where S2.Abs_Status = 0 and S2.MONTH = S.MONTH
) and Abs_status = 1

update s 
set s.Abs_Status = 2
from SourceData S
where 2 = (
  select top 1 S2.Abs_Status from SourceData S2
  where S2.Abs_Status <> 1 and S2.WeekNum > S.WeekNum
  order by S2.WeekNum asc
) and Abs_status = 1

update s 
set s.Abs_Status = 2
from SourceData S
where 2 = (
  select top 1 S2.Abs_Status from SourceData S2
  where S2.Abs_Status <> 1 and S2.WeekNum < S.WeekNum
  order by S2.WeekNum desc
) and Abs_status = 1

select * from [SourceData];

第一次更新会将整个月份 Abs_Status = 1

的行的 Abs_Status 更新为 2

接下来的 2 次更新会将缺席之前/之后的部分月份更新为 2。

SQL Fiddle

SQL 确定缺勤是否为“辍学”

SQL to determine if a non-attendance is a “DROPOUT”

sql

sql-server

time-and-attendance