All values should be undefined:
$a =  
$b =  
$c =  
$d =  
$e =  
First of all assign a value:
Now we have some 'Umlaute':
Now lets look what we are getting from this:
(this is the value in $a) (this is the value in $a) äöü
And now a and b together: (this is the value in $a)(this is the value in $a) äöü
Here we have some HTML tags within the perl code, Embperl will delete them!
57
SELECT *  FROM a ORDER BY b USING <; Hi There>
Here we have something which looks like a HTML tag, but does not start with
a character, Embperl does not change them!
SELECT * FROM a ORDER BY b USING <; Hi There>
Embperl will also translate HMTL escapes to the right characters i.e. $a < 6 will get the perl expression $a < 6: 
1
Now they should have a value
$a = (this is the value in $a) 
$b = (this is the value in $a) äöü 
$c = 57 
$d = 1 
$e = 2 
Ok.