data imslib.view1 combine;
   modify imslib.view1 imslib.view2;
   by key;
   select (_iorc_);
      when(%sysrc(_sok)) output combine;
      when(%sysrc(_dsenmr)) do;
         _error_ = 0;
         put 'no match for by key = ' key;
      end;
      otherwise do;
         _error_ = 0;
         put 'Unexpected IORC = ' _iorc_ ' Processing terminated.';
         stop;
      end;
   end;
run;