I'd try a different approach.

$sql = 'select * from EMP where EMPNO=&eno and DEPTNO=&dno and JOB=&jo
+b';
my @fields;
if (my($where) = $sql =~ /\swhere\s+(.*)/i) {
   @fields = map /(\S*)=&/, split /\sand\s/i, $where;
}
[download]

(In English: parse out the "where" expression. Split it into terms on the "and" keyword. For each term, see if it matches the pattern of an identifier followed by "=&" and keep the identifier if it does match.)

Hmm, are you sure you want the "=" to be part of the match?

p.s. This is in my opinion a somewhat fishy approach, as it depends strongly on the query being formatted in a specific way. This might suffice for your needs, if the SQL is indeed as restricted as it appears here. In other cases, I'd look at better SQL parsers, like SQL::Parser, or Ovid's article on tokenizing SQL on perl.com