出勤时间

雇员表出勤表中，只有一个字段为上班总工时，需要计算出正常上班工时，缺勤工时和加班工时。

CREATE FUNCTION [dbo].[udf_WorkingHours]
(   
)
RETURNS @WorkingHours TABLE([WorkTicketId] INT,[OperatorDate] DATETIME,[NormalWorkTime] DECIMAL(18,6),[AbsentationTime] DECIMAL(18,6),[OverTime] DECIMAL(18,6))
AS
BEGIN
    INSERT INTO @WorkingHours 
    SELECT DISTINCT [WorkTicketId],[OperatorDate],
    --正常工时
    (CASE WHEN (ISNULL([Presence],0) < 8) THEN [Presence]WHEN (ISNULL([Presence],0) >= 8) THEN 8 END),
    --缺勤工时
    (CASE WHEN (ISNULL([Presence],0) < 8) THEN (8- [Presence]) WHEN (ISNULL([Presence],0) >= 8) THEN 0 END),            
    --加班工时
    (CASE WHEN (ISNULL([Presence],0) <= 8) THEN 0 WHEN (ISNULL([Presence],0) > 8) THEN ([Presence]- 8) END)            
    FROM [dbo].[udf_WorkTicketRecorded]()
    RETURN
END