use DBI;
  
my $dbh = DBI->connect( "DBI:mysql:dbname=$db", $user, $passwd, {
    PrintError => 0,
    RaiseError => 1,
    AutoCommit => 1,
} ) or die DBI->errstr;
 

$dbh->do( "CREATE TEMPORARY TABLE test_table AS SELECT * FROM Abteilung AS abt 
           LEFT OUTER JOIN Mitarbeiter AS mit ON abt.AbtNr = mit.AbtNr" );