While you should be commended to point at a lowest common denominator solution it should be pointed out that the LIMIT keyword is non-standard (and your code snippet is also missing the $sth->execute call :-).

It shouldn't be necessary to even fetch a single row for this. A WHERE clause that evaluates to false achieves this with minimal impact on the server:

use strict;
use DBI;
my $dbh = DBI->connect('DBI:database_type:database_name','user','passw
+ord') || die DBI->errstr;
my $sth = $dbh->prepare("SELECT * FROM table_name WHERE 0=1") || die $
+dbh->errstr;
$sth->excecute || die $sth->errstr;
my @column_names = @{$sth->{NAME}};
$sth->finish();  # may be unnecessary
$dbh->disconnect();
[download]

Update Fixed typo in WHERE clause...

Michael