缺勤天数统计的处理示例.sql

--计算两个日期之间相差的工作天数
CREATE FUNCTION f_WorkDateDiff(
@dt_begin datetime,
@dt_end datetime)
RETURNS int
AS
BEGIN
 DECLARE @workday int,@i int,@bz bit,@dt datetime
 IF @dt_begin>@dt_end
  SELECT @bz=1,@dt=@dt_bsegin,@dt_begin=@dt_end,@dt_end=@dt
 ELSE
  SET @bz=0
 SELECT @i=DATEDIFF(Day,@dt_begin,@dt_end)+1,
  @workday=@i/7*5,
  @dt_begin=DATEADD(Day,@i/7*7,@dt_begin)
 WHILE @dt_begin<=@dt_end
 BEGIN
  SELECT @workday=CASE
   WHEN (@@DATEFIRST+DATEPART(Weekday,@dt_begin)-1)%7 BETWEEN 1 AND 5
   THEN @workday+1 ELSE @workday END,
   @dt_begin=@dt_begin+1
 END
 RETURN(CASE WHEN @bz=1 THEN -@workday ELSE @workday END)
END
GO

--测试数据
CREATE TABLE tb(Name varchar(10),WorkDate datetime)
INSERT tb SELECT 'aa','2005-01-03'
UNION ALL SELECT 'aa','2005-01-04'
UNION ALL SELECT 'aa','2005-01-05'
UNION ALL SELECT 'aa','2005-01-06'
UNION ALL SELECT 'aa','2005-01-07'
UNION ALL SELECT 'aa','2005-01-10'
UNION ALL SELECT 'aa','2005-01-14'
UNION ALL SELECT 'aa','2005-01-17'
UNION ALL SELECT 'bb','2005-01-11'
UNION ALL SELECT 'bb','2005-01-12'
UNION ALL SELECT 'bb','2005-01-13'
UNION ALL SELECT 'bb','2005-01-10'
UNION ALL SELECT 'bb','2005-01-14'
UNION ALL SELECT 'bb','2005-01-20'
GO

--缺勤统计
DECLARE @dt_begin datetime,@dt_end datetime
SELECT @dt_begin='2005-1-1', --统计的开始日期
 @dt_end='2005-1-20'        --统计的结束日期

--统计
SELECT Name,Days=SUM(Days) FROM(
 SELECT Name,Days=dbo.f_WorkDateDiff(
   DATEADD(Day,1,WorkDate),
   ISNULL(DATEADD(Day,-1,(
    SELECT MIN(WorkDate) FROM tb aa
    WHERE Name=a.Name
     AND WorkDate>a.WorkDate AND WorkDate<=@dt_end
     AND NOT EXISTS(
      SELECT * FROM tb
      WHERE WorkDate>@dt_begin AND WorkDate<=@dt_end
       AND Name=aa.Name
       AND dbo.f_WorkDateDiff(WorkDate,aa.WorkDate)=2))
    ),@dt_end))
 FROM(
  SELECT Name,WorkDate FROM tb
  WHERE WorkDate>=@dt_begin AND WorkDate<@dt_end
  UNION ALL --为每组编号补充查询起始编号是否缺号的辅助记录
  SELECT DISTINCT Name,DATEADD(Day,-1,@dt_begin) FROM tb
 )a
 WHERE (@@DATEFIRST+DATEPART(Weekday,WorkDate)-1)%7 BETWEEN 1 AND 5
  AND NOT EXISTS(
   SELECT * FROM tb
   WHERE WorkDate>@dt_begin AND WorkDate<=@dt_end
    AND Name=a.Name
    AND dbo.f_WorkDateDiff(WorkDate,a.WorkDate)=-2)
)aa GROUP BY Name
/*--结果
Name       Days
---------------- -----------
aa         6
bb         8
--*/