The Aggregate For Several Fields In Same Row?

I need to find an aggregate for several fields in a row
e.g. Max(date1, date2, ..., dateN)

I can pass this to a delimited string,
pass the string to an UDF that returns a table
and run Max(tablefield) on that UDF

Unfortunately I can only get this working for 1 delimited string at a time

Ideally I would want to include the function in a SELECT statement, e.g. something like

SELECT t1.a, dbo.MaxOfFieldValues(t1.d1+','+t1.d2+...+','+t2.dN )
FROM t1

I got it working with the following two udfs, but I am sure visitors here have solved this a bit smarter:


ALTER Function [dbo].[MaxOfFieldValues]
(
@ListOfValues varchar(8000)
, @delimiter varchar(10) = ','
)
RETURNS VARCHAR(8000)
AS
BEGIN
--Need to get the maximum changedate first
--pass the fields as one value (a delimited string)
--and calc the max
declare @result varchar(8000)
declare @remainder varchar(8000)
set @remainder = @ListOfValues
declare @NoOfItems int --items = delimiters +1
SET @NoOfItems = (len(@ListOfValues) - Len(Replace(@ListOfValues,@delimiter,''))/Len(@ListOfValues))+1
declare @counter int
set @counter =1
set @result = dbo.TakePart(@remainder,@delimiter,@counter)
WHILE @counter <= @NoOfItems
BEGIN
set @counter = @counter + 1
IF @result < dbo.TakePart(@remainder,@delimiter,@counter)
BEGIN
SET @result = dbo.TakePart(@remainder,@delimiter,@counter)
END
END
RETURN (@result)
END

ALTER FUNCTION [dbo].[TakePart]
(
@param varchar(8000)
, @delimiter varchar(10)
, @NumPart int
)
RETURNS varchar(8000)
AS
BEGIN
--Note: maybe smarter to whack the delimiter to the end of the string to avoid the IF statement
declare @result varchar(8000)
declare @remainder varchar(8000)
declare @counter int
set @result = ''
set @remainder = @param
set @counter = 1
WHILE @counter < @Numpart
BEGIN
SET @remainder = SUBSTRING(@remainder,CHARINDEX(@delimiter,@remaind er,1)+Len(@delimiter),8000)
SET @counter = @counter +1
END

IF @counter > (len(@param) - Len(Replace(@param,@delimiter,''))/Len(@delimiter))
BEGIN
SET @result = @remainder
END
ELSE
BEGIN
SET @result = LEFT(@remainder,CHARINDEX(@delimiter,@remainder,1) -1)
END

RETURN @result
END


Cheers

Drio