Determine Time Difference on a holiday

-- Create temp table for demonstration
Declare  @tb table (emp_name varchar(30),time_in DateTime, time_out DateTime);
insert into @tb (emp_name,time_in,time_out) values( 'Joey','2013-12-24 20:00:00','2013-12-25 04:30:00');
insert into @tb (emp_name,time_in,time_out) values( 'Not Joey','2013-12-24 20:00:00','2013-12-24 22:30:00');
insert into @tb (emp_name,time_in,time_out) values( 'Still Not Joey','2013-12-26 20:00:00','2013-12-26 22:30:00');
Declare @Holiday DateTime;
Set @Holiday = '2013-12-25 00:00:00'
--
-- Execute the SELECT statement
--
select
 emp_name,CAST(time_in as smalldatetime) As TimeIn,CAST(time_out as smalldatetime) as TimeOut,
 DATEADD(
    second,
    DATEDIFF(second,time_in,time_out),
    TIMEFROMPARTS(0,0,0,0,0)) as Total_Hours,
 DATEADD(second,
   IIF( DATEDIFF(second,
        IIF(@Holiday > time_in,@Holiday,time_in),
        IIF(DATEADD(Hour,24,@Holiday)< time_out,DATEADD(Hour,24,@Holiday),time_out))<0,0,
    DATEDIFF(second,
        IIF(@Holiday > time_in,@Holiday,time_in),
        IIF(DATEADD(Hour,24,@Holiday)< time_out,DATEADD(Hour,24,@Holiday),time_out))),TIMEFROMPARTS(0,0,0,0,0)) as Holiday_Hours
 from @tb

emp_name        TimeIn              TimeOut             Total_Hours Holiday_Hours
Joey            2013-12-24 20:00:00 2013-12-25 04:30:00   08:30:00    04:30:00
Not Joey        2013-12-24 20:00:00 2013-12-24 22:30:00   02:30:00    00:00:00
Still Not Joey  2013-12-26 20:00:00 2013-12-26 22:30:00   02:30:00    00:00:00

select
 emp_name,time_in,time_out,
 DATE_ADD(TIMEFROMPARTS(0,0,0,0,0), INTERVAL TIME_TO_SEC(TIMEDIFF(time_out,time_in)) SECOND) as Total_Hours,
 DATE_ADD(TIMEFROMPARTS(0,0,0,0,0), INTERVAL
    IIF(
      TIME_TO_SEC(TIMEDIFF(
    IIF(
         DATE_ADD('2013-12-25 00:00:00',INTERVAL 24 HOUR) < time_out,
     DATE_ADD('2013-12-25 00:00:00',INTERVAL 24 HOUR),time_out
           ),
         IIF('2013-12-25 00:00:00' > time_in,'2013-12-25 00:00:00',time_in)
                )
    )<0,0,
    TIME_TO_SEC(
    TIMEDIFF(
        IIF(DATE_ADD('2013-12-25 00:00:00',INTERVAL 24 HOUR) < time_out,DATE_ADD('2013-12-25 00:00:00',INTERVAL 24 HOUR),time_out)
        ),
            IIF('2013-12-25 00:00:00' > time_in,'2013-12-25 00:00:00',time_in)
        )
    ) SECOND) as Holiday_Hours
 from @tb