 MERGE sort-file-1
 ~~~~~
    { ON { ASCENDING  } KEY identifier-1... }...
         { ~~~~~~~~~  }
         { DESCENDING }
           ~~~~~~~~~~
    [ WITH DUPLICATES IN ORDER ]
           ~~~~~~~~~~
    [ COLLATING SEQUENCE IS alphabet-name-1 ]
      ~~~~~~~~~
      USING file-name-1 file-name-2...
      ~~~~~
    { OUTPUT PROCEDURE IS procedure-name-1    }
    { ~~~~~~ ~~~~~~~~~                        }
    {       [ THRU|THROUGH procedure-name-2 ] }
    {         ~~~~ ~~~~~~~                    }
    { GIVING file-name-3...                   }
    { ~~~~~~                                  }
