my $filter = "('Y' || 'N')";
my $sth = $dbh->prepare(q{SELECT name FROM catagories WHERE catagories.workrelated = ? ORDER BY name});
$sth->execute($filter);

##</code><code>##

my $sth = $dbh->prepare(q{SELECT name FROM catagories WHERE catagories.workrelated = ? ORDER BY name});
$sth->execute("('Y' || 'N')");

##</code><code>##

my $sth = $dbh->prepare(q{SELECT name FROM catagories WHERE catagories.workrelated = ('Y' || 'N') ORDER BY name});
$sth->execute();