my $sqlStatement = qq~SELECT Tabelle1.Kundennummer, Tabelle1.Name,
    Tabelle1.Telefon, Tabelle2.Rechnungsbetrag FROM Tabelle1 JOIN Tabelle2 USING(Kundennummer)

my $dsn = "DBI:ODBC:Kunden";
 my $dbh = DBI->connect($dsn)
     or die "Error: couldn't connect to '$dsn': $DBI::errstr\n";