using mysql errnos to show up a user friendly error message

[suro]

Is it considered normal using mysql errno-s to know what the error is and show up a user friendly error message?

e.g. for a duplicate entry mysql errno is 1062 and I show up a user friendly error message.
I ask this because there is also another way of doing it.

 if (@mysql_result($result,0,0)>0) {
       error('A user already exists with your chosen userid.\\n'.
             'Please try another.'); 

As shown in one of sitepoints tutorials

So which way is better?

[Dean C]

Personally I use a database class and then handle any errors internally and use a method within that class to output a user-friendly error message if there is some kind of MySQL error.