Provides a summary of totals for one or more numeric fields in
       the current collection. The summary is sorted according to the
       values in one or more fields of the current collection. The
       summary includes subtotals for control groups. The summary can
       be written to a file or an output device.

       Format

                                        [    {file-spec  } ]
         SUM  print-list  BY  sort-list [ ON {*.prompt   } ]
                                        [    {           } ]