SAS仅依次解析了和各一遍
故&rc 值是low

这里可能使用call symput会好些

%语句 仅仅是文本替换而已

哦～谢谢～ 我苦思冥想了很久:S

3# oxygenmz

编译次序造成的；

%let rc=Begin;
%macro test;
data out;
set sashelp.prdsale nobs=totalobs;
new=totalobs;
%if totalobs >10 %then %do;
%let rc=high;
%end;
%else %do;
%let rc=low;
%end;
run;
%mend;
%let rc= Before Execution;
%test
%put answer: &rc;


这样就变high了













1# oxygenmz

Others already pointed out where the problem is.

Here is a simpler version of you codes.

%macro nobs(dsn=);
    data _null_;
      if 0 then set &dsn nobs=nobs;   ***note nobs is available at compiling time. Not needed to open it and read it;
      if nobs >10 then call symputx('rc','High');
      else  call symputx('rc','Low');
    run;
    %put rc=&rc;
%mend;

%nobs(dsn=sashelp.class)
data t1;
x=1;
run;
%nobs(dsn=t1)