The easiest way is to move the comma printing to the front of the loop, and add a flag to control printing it: 
   my $add_comma=0;
   while ( my ( $cat, $schem, $tn, $cn, $dt, $tyn, $cs, $bl, $dd, $npr
+, $nul) = $sth->fetchrow_array()) { 
      if ($add_comma++) {
          print ",\n";
      }
      print "\t$cn ";
      if (($tyn eq 'DATETIME') || ($tyn eq 'DOUBLE')) {
         print "$tyn";
      } else {
         print "$tyn($cs)";
      }
      print " not null" if ($nul == 0);
   }

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Remember: There's always one more bug.

In reply to Re: Don't print on the last loop by jdhedden
in thread Don't print on the last loop by omega_monk

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