/* pgm 10.2                 */
 /*                           */
 /* simple example of set     */
 /*  with pdv 'IN' variables  */
 /*                           */
  data a ;                    * first dataset with w x y ;
    input w x y ;             * two observations ;
    cards ;
     2  1  4
     3  3  0
    ;
 run ;
  data b ;                    * second dataset with x y z ;
    input x y z ;             *  three observations ;
    cards ;
     2  1  0
     4  0  3
     6  2  2
    ; 
 run ;
 /* put them together         */
 /*   expect 5 obs and 4 vars */
   data aandb ;
     set a(in=isita) b(in=isitb) ;
 /* IN= variables only in PDV */
	 put x= y= isita= isitb= ;
	 * put _all_ ;
     itsa = 'no ' ;           * space so no length statement ;
     if( isita ) then itsa = 'yes' ;
     if( isitb ) then itsb = 'yes' ;
 run ;
 /* print them out            */
 /*  will we see isita, isitb?*/
   proc print data=aandb ;
     title 'set a b' ;
 run ;