how to get max date from a list

Hi All
i'm nt good at coding. could anyone help me how to get the max date from several datetime columns? we have a provider table:
Provider (Prov_Num, Prov_Name, Prov_Address, Prov_Phone, Date_1, Date_2, Date_3, Date_5, Date_6)
how could i get the maximum date of Date_1, Date_2, Date_3, Date_5, Date_6 in the query?
thanks in advance.

Create function
CREATE FUNCTION get_max_date(
@d1 datetime ,@d2 datetime ,@d3 datetime ,@d4 datetime ,@d5 datetime ) returns datetime
as
begin
declare @max_date datetime
set @max_date = @d1

if @max_date > @d2
set @max_date = @d2

if @max_date > @d3
set @max_date = @d3


if @max_date > @d4
set @max_date = @d4


if @max_date > @d5
set @max_date = @d5

return @max_date
end

how to call
select dbo.get_max_date(Date_1, Date_2, Date_3, Date_5, Date_6)
from Provider
quick test
print dbo.get_max_date(getdate(), getdate()+4, getdate()+5, getdate()+3,
getdate()+2)

thank you All
i picked up the one which creates a function and call it from SQL query.
have a good day.

[quote user="Madhivanan"]Note that you need to change > to < in the function to pick max date[/quote]
oh my mistake, change > to be <
thanks Madhivanan