my $rows = $dbh->selectall_arrayref("SELECT * FROM foo");

# Now @$rows contains all the row data.
# Use @$rows like $rows->[$row_number]->[$column_number]...
foreach my $row (@$rows)
{
     # ...or @$row like $row->[$column_number]
}

# Repeat as required, as long as $rows is still defined.

# $sth->finish();  # Update per pope (Not required, no $sth defined)