Something like this?

my @form = map { $cgi->param("form$_") } 0..21;

while (my $line = <DB>) {
   my @split_sp_data = split(/,/, $line);

   for my $i (0..21) {
      if (index($split_sp_data[$i], $form[$i]) >= 0) {
         print(qq(<a href="$split_sp_data[$i]">$split_sp_data[$i]</a>)
+);
      }
   }
}
[download]

index is faster than regexps when search for a static string (as opposed to a regexp).

Update: oops! Changed index(...) != 0 to index(...) >= 0. Thanks, InfiniteSilence.