Date:         Mon, 4 Mar 2002 13:34:49 -0500
Reply-To:     Charles Patridge <Charles_S_Patridge@PRODIGY.NET>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Charles Patridge <Charles_S_Patridge@PRODIGY.NET>
Subject:      Re: how to stop creating a data set
Comments: To: "P. L" <li_9@HOTMAIL.COM>

Dear PI,

What you can do is test to see if you have an empty dataset and then
determine what you want to do - that is skip some logic or execute some
logic (such as delete a dataset).

Here is some code to get the number of OBS in a datatset (not the most
efficient method but it does work).


*********************************************************************;
**  PROGRAM: EMPTYYN  (MACRO)                                        ;
**  AUTHOR: CHUCK PATRIDGE                                           ;
**  DATE: 10/12/94                                                   ;
**  PURPOSE: DETERMINE IF A SAS DATASET IS EMPTY.                    ;
**  INPUT PARAMETER: DSNAME (NAME OF SAS DATA SET)                   ;
**                   ALSO CAN BE BLANK ( USE LAST DATASET CREATED)   ;
**  OUTPUT: WILL CREATE THE FOLLOWING GLOBAL MACRO VARIABLES         ;
**            EMPPTYYN               Y=EMPTY, N=NONEMPTY             ;
**            NUMOBS             WHICH PROVIDES NUMBER OF RECORDS    ;
**            DSN                WHICH PROVIDES NAME OF DATA SET     ;
** SAMPLE CALL: %EMPTYYN(DATASET)                                    ;
**                                                                   ;
*********************************************************************;
%GLOBAL EMPTYYN NUMOBS DSN;
%MACRO EMPTYYN(DSNAME);
  DATA _NULL_;
   IF "&DSNAME " = " " THEN CALL SYMPUT('DSNAME','_LAST_');
  RUN;

  DATA _NULL_;
   IF 0 THEN SET &DSNAME NOBS=NUMOBS;
   IF NUMOBS > 0 THEN EMPTYYN = 'N';
                 ELSE EMPTYYN = 'Y';
   CALL SYMPUT('EMPTYYN',PUT(EMPTYYN, $1.));
   CALL SYMPUT('NUMOBS' ,PUT(NUMOBS , BEST.));
   CALL SYMPUT("DSN"    ,PUT("&DSNAME" , $VARYING17.));
   STOP;
  RUN;
 %MEND EMPTYYN;
********  END OF SAS PROGRAM  ****************;


You only need to use the maco variable "numobs", the other two are not
needed in your case.

HTH,
Charles Patridge
Email: Charles_S_Patridge@prodigy.net