OT Calculation based on

how to calculate OT?

please help me

ex:

declare @OT_Hours varchar(44)--decimal(18,1)

declare @WorkHours varchar(44)--decimal(18,2)

declare @ActualHours varchar(44)--decimal(18,2)

select @WorkHours=

right('0'+ cast( cast((WorkMin/60) as int) as varchar(44)),2)+ ':'+ right('0'+ cast(cast(WorkMin as int)-

(cast((WorkMin/60) as int)*60) as varchar(44)),2) from Attendance_Master

where left(convert(char(6), AM_date,112),6) =

left(convert(char(8),@date,112),6) and AM_EmpCode=@emp_code and (AM_Status='O' OR AM_Status='P')

set @ActualHours='08:00'

set @OT_Hours=(@WorkHours-@ActualHours)