Problem creating Function that converts num to char

[aruba]

I am trying to create a function that changes the first 2 numbers to 'A' when the number reaches 1,000,000. The source is a numeric datatype so I need to convert it as well. Here is my code, which works as long as it's not a function. Any help would be greatly appreciated!

create function wkctl.parentwo_convertToP3(@parentwo bigint)
returns varchar
as
begin

declare @char_parentwo varchar

if @parentwo between 999999 and 1099999
select replace(@parentwo,substring(convert(varchar(15),@parentwo),1,2),'A')
set @char_parentwo = @parentwo
return (@char_parentwo)
end

 

[Jamfool]

instead of the select

set @parentwo = replace(@parentwo,substring(convert(varchar(15),@parentwo),1,2),'A')

 

[aruba]

Thank you! That solved my problem!