my $sql = "SELECT Typ, Schluessel, Anrede, Name, Zusatz, Strasse, PLZ, Ort, Email, Internet, Lief_KDNR, Memos FROM Adressen WHERE Nummer = '".$adress_nr."';";
my $sth = $dbh->prepare($sql);
$sth->execute;

my @row = map { defined $_ ? $_ : '' } $sth->fetchrow_array;