Date:         Tue, 20 Jul 2004 10:22:10 -0400
Reply-To:     "Chen, Jian" <OZZ6@CDC.GOV>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Chen, Jian" <OZZ6@CDC.GOV>
Subject:      Macro question
Content-Type: text/plain; charset="us-ascii"

Could some one explain why the following macro doesn't work?

The problem is with variable emplty03.

%macro test1(tribe2);

%if %sysfunc(exist(&tribe2.nhanes03))=0 %then
%do;
        %let emplty03=1;
        data &tribe2.nhanes03;
        set _null_;
        run;
%end;

%if &emplty03=1 %then
%put data not available;

%mend;

%test1;

LOG:
 A character operand was found in the %EVAL function or %IF condition
where a numeric
       operand is required. The condition was: &emplty99=1 and
&emplty00=1 and &emplty01=1 and
       &emplty02=1 and &emplty03=1



How could I check if a dataset is _null_?

I need to check if a dataset(one) is _null_, I do the following:

If one=_null_ then ...

It doesn't seem to work that way.