SQL Server 2012 :: Calculating Working Hours Between 2 Dates

This function will return working hours between given 2 dates. This function assumes that the break is between 9:45 AM and 10 AM and that Lunch is between 12:30 PM and 1 PM. This function also assumes that the working hours are between 7:30 AM and 4 PM. There is a section for public holidays there. We have a table for that you might not so that piece needs to be fixed.

CREATE function [dbo].[fnc_myHinkley_ASSY_CalcWorkingMinutes] (@StartDate datetime, @EndDate datetime)
RETURNS decimal(14,2)
/*
Programmer: Goran Borojevic
Date: 5/14/2014

This function will return working hours between given 2 dates. This function assumes that the break is between 9:45 AM and 10 AM and that Lunch is between 12:30 PM and 1 PM. This function also assumes that the working hours are between 7:30 AM and 4 PM.
*/
AS
BEGIN

--check if one of the dates is null
if @StartDate is null or @EndDate is null
RETURN 0

[code]...