如何判断数据集没有观测？

1. data aaa;
   
2. input x y;
   
3. cards;
   
4. 1 2
   
5. 3 4
   
6. ;
   
7. run;
   
8. 
   
9. data bbb;
   
10.         set aaa;
    
11.         where x>3;
    
12. run;

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如何在macro中判断bbb数据集没有观测或为空数据集？谢谢！

1. data aaa;
   
2. input x y;
   
3. cards;
   
4. 1 2
   
5. 3 4
   
6. ;
   
7. run;
   
8. data bbb;
   
9. set aaa;
   
10.         where x>3;
    
11. run;
    
12. 
    
13. %macro checknobs(dsn);
    
14. proc sql noprint;
    
15. select nobs into:obscount from dictionary.tables
    
16. where trim(libname)||"."||memname="%upcase(&dsn)";
    
17. quit;
    
18. %if &obscount >0 %then %do;
    
19. proc print data=&dsn(obs=10);
    
20. title1 "a few observations from &dsn";
    
21. run;
    
22. %end;
    
23. %else %do;
    
24. data _null_;
    
25. file print notitles;
    
26. put "there are no observations in &dsn";
    
27. run;
    
28. %end;
    
29. %mend checknobs;
    
30. %checknobs(work.bbb)

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1. %macro check_obs(dsn);
   
2. %let dsid=%sysfunc(open(&dsn,i));
   
3. %let obs=%sysfunc(attrn(&dsid,nlobs));
   
4. %if &obs>0 %then %put "&dsn has &obs obs";
   
5. %else %put "&dsn has 0 obs";
   
6. %let rc=%sysfunc(close(&dsid));
   
7. %mend;
   
8. %check_obs(bbb)

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你指的观测是什么的观测？

    data aaa;
    input x y;
    cards;
    1 2
    3 4
    ;
    run;

    data bbb;
            set aaa;
            where x>3;
    run;

        proc sql noprint;
        select count(*) into: count1 from bbb;
        quit;
%macro count;
%if &count1 = 0 %then %do;
data _null_;
%put 'there is no observation in data set bbb';
run;
%end;
%else %do;
proc print data=bbb;
run;
%end;
%mend;
%count

data _null_;
      if _n_=0 then set bbb nobs=nobs;
     if nobs=0 then put 'bbb dataset has no observation';
     stop;
run;