my @what = split(/\s+/, $what);
shift @what if $what[0] eq '';  # skip leading empty fields
my $first = 1;
foreach (@what) { 
    push (@$where, 'AND') unless $first;
    push (@$where, [
                        { subject => ['LIKE', "\%$_\%"] },
                        'OR',
                        { message => ['LIKE', "\%$_\%"] },
                   ]);
    $first = 0;               
}             

$dbx->select({
    fields => 'reference, subject, name',
    table  => 'boardmessage',
    where  => $where,
});