...
my $dbh = database->connect_mysql();
my $sql = "select *  FROM mytable WHERE date < DATE_ADD(NOW(), INTERVAL -30 DAY)";
my $sth = $dbh->prepare($sql) or "Can't select from table: ",$dbh->errmsg;
   $sth->execute();
my $data = $sth->fetchrow_hashref(); # <- this line x

for (my $i = 0; $i < @{$data}; $i++) {

     my $user = $data->[$i]{'user'}) || '';
     my $id = $data->[$i]{'id'}) || '';

     print "Data Test: $user - $id<br>";
}

....

#Not an ARRAY reference at  line x. Error