SAS: do not send email when no records

Question

I'm new to SAS base and I am trying to either add a line saying all ID's transferred when nobs=0 Here's what I added on what Alex gave me which print the ID's when there are any in the data set workgo.recds_not_processed. I added nobs=0 condition but it is not sending the ID's when they are present.

data _null_;
   length id_list $ 3000;
   retain id_list '';
   file mymail;
   SET set workgo.recds_not_processed nobs = nobs end = eof;
   IF nobs = 0 then PUT "All ID's transferred successfully";      
   else  if _n_ = 1 then do;
      put 'Number of records not processed=' nobs;
      put 'The IDs are:';
   end;
   /* Print the IDs in chunks */
   if length(strip(id_list)) > 2000 then do;
      put id_list;
      call missing(id_list);
   end;
   call catx(', ', id_list, id);
   if eof then put id_list;
 run;

Answer 1

You are very nearly there - the unmatched end spotted by Joe and the double set that I pointed out were the only obvious errors preventing your code from working.

The reason you got no output when dealing with an empty dataset is that SAS terminates a data step when it tries to read a record from a set statement and there are none left to read. One solution is to move your empty dataset logic before the set statement.

Also, you can achieve the desired result without resorting to retain and call catx by using a double trailing @@ in your put statement to write to the same line repeatedly from multiple observations from the input dataset:

data recds_not_processed;
    do id=1 to 20;
        output;
    end;
run;

data _null_;
    /*nobs is populated when the data step is compiled, so we can use it before the set statement first executes*/
    IF nobs=0 then
        do;
            PUT "All IDs transferred successfully";
            stop;
        end;
    /*We have to put the set statement after the no-records logic because SAS terminates the data step after trying to read a record when there are none remaining.*/
    SET recds_not_processed nobs=nobs end=eof;

    if _n_=1 then
        do;
            put 'Number of records not processed=' nobs;
            put 'The IDs are:';
        end;

    /* Print the IDs in chunks */
    if eof or mod(_N_, 5)=0 then
        put id;
    else
        put id +(-1) ', ' @@;
run;