If you have a modern version of Microsoft SQL Server, then you can keep it simple and use the build-in trim method.
TRIM ( [ LEADING | TRAILING | BOTH ] [characters FROM ] string )
Consider this code:
declare @result nvarchar(50) =N' hello world!, ';
print len(@result)
set @Result= TRIM(BOTH ', ' from @Result)
print @result
print len(@result)
the answer will be:
16
hello world!
12
To make it a little clearer, you can look at this sample, which demonstrates the removal of the comma, the white space, and the exclamation mark.
declare @result nvarchar(50) =N' hello world!, ';
print len(@result)
set @Result= TRIM(BOTH ', !' from @Result)
print @result
print len(@result)
the answer is now:
16
hello world
11
You can see each character in the [character] parameter is removed.
I used a variable in the demo but it works in columns just as well.