if cast(SERVERPROPERTY('ProductVersion') as sysname) not like '11.%'
	begin

		begin try
			drop function dbo.EOMONTH
		end try
		begin catch
			-- dummy
		end catch
		go

		create function dbo.EOMONTH(@start_date datetime, @month_to_add int = 0)
		returns datetime as
			begin
				return dateadd(month,datediff(month,-1,@start_date) + @month_to_add, -1)
			end
		go

	end
else
	print '-- Function EOMONTH() part of this SQL version'

begin try
	drop function dbo.BOMONTH
end try
begin catch
	-- dummy
end catch
go

create function dbo.BOMONTH(@start_date datetime, @month_to_add int = 0)
returns datetime as
	begin
		return dateadd(day, 1, dbo.EOMONTH(@start_date, @month_to_add - 1 + @month_to_add))
	end
go


begin try
	drop function dbo.DIMONTH
end try
begin catch
	-- dummy
end catch
go

create function dbo.DIMONTH(@start_date datetime, @month_to_add int = 0)
returns int as
	begin
		return datepart(day, dbo.EOMONTH(@start_date, @month_to_add))
	end
go


begin try
	drop function dbo.BOWEEK
end try
begin catch
	-- dummy
end catch
go

create function dbo.BOWEEK(@start_date datetime, @week_to_add int = 0)
returns datetime as
	begin
		return dateadd(week,datediff(week,-1,@start_date) + @week_to_add,-1)
	end
go


begin try
	drop function dbo.EOWEEK
end try
begin catch
	-- dummy
end catch
go

create function dbo.EOWEEK(@start_date datetime, @week_to_add int = 0)
returns datetime as
	begin
		return dateadd(day, -1, dbo.BOWEEK(@start_date, @week_to_add + 1))
	end
go


begin try
	drop function dbo.DATEFROMPARTS
end try
begin catch
	-- dummy
end catch
go

create function dbo.DATEFROMPARTS(@year int, @month int, @day int)
returns datetime as
	begin
		return dateadd(day, @day - 1, dateadd(month, @month - 1, dateadd(year, @year - 1900, 0)))
	end
go


begin try
	drop function dbo.DATETIMEFROMPARTS
end try
begin catch
	-- dummy
end catch
go

create function dbo.DATETIMEFROMPARTS(@year int, @month int, @day int, @hour int, @minute int, @second int)
returns datetime as
	begin
		return dateadd(second, @second, dateadd(minute, @minute, dateadd(hour, @hour, dateadd(day, @day - 1, dateadd(month, @month - 1, dateadd(year, @year - 1900, 0))))))
	end
go

/*
	DEMO
*/
declare @mydate datetime
set @mydate = getdate()

select	dbo.BOMONTH(@mydate,0) as begin_of_month,
		dbo.EOMONTH(@mydate,0) as end_of_month,
		dbo.DIMONTH(@mydate,0) as days_in_month,
		dbo.BOWEEK(@mydate,0) as begin_of_week,
		dbo.EOWEEK(@mydate,0) as end_of_week,
		dbo.BOWEEK(@mydate,1) as begin_of_next_week,
		dbo.EOWEEK(@mydate,1) as end_of_next_week,
		dbo.DATEFROMPARTS(2011,09,30) as datefromparts,
		dbo.DATETIMEFROMPARTS(2011,09,30,16,59,59) as datetimefromparts