my $rowid = $q->param('rowid');  # get the value from our CGI.pm object

# search the first column for the rowid, and store the first match in $row_ref
my ($row_ref) = grep { $_->[0] eq $rowid } @ary;

# output an html table containing column head labels and a row of data
print '<table>',
  '<tr><td>rowid</td><td>course1</td><td>course2</td></tr>',
  '<tr>', (map {"<td>$_</td>"} @$row_ref), '</tr>',
  '</table>';