I don't know if you would want to do this but ....
you can alway do an end run on DBI with Oracle
by doing something like this ...

my $cmd="sqlplus scott/tiger\@whatever";

open SQLPLUS, "|$cmd" or die "Ah poo!:$!\n";
print SQLPLUS<<DOIT;
select to_char(large_number,'999999999999') from mytable;
DOIT
close SQLPLUS;
[download]

... might want to save this as a last resort.