use DBI;
use Spreadsheet::WriteExcel;
my $DB=DBI::connect( ... connection args for oracle DB ... );
my $ar = $DB->selectall_arrayref('select * from table');
my $XLWB = Spreadsheet::WriteExcel->new('table.xls');
my $XLWS = $XLWB->add_worksheet('table');
my $row = 0;
$XLWS->write_row($row,0,$_) for @$ar;