高级优先级队列(Advanced priority queue)

 在set语句中使用point=时，还需要包含stop语句以防止无限循环。 尝试这个： 
 
%let buffer = 3;     
data dates_with_buffer; 
   do i = -1*&buffer. to &buffer.; 
      do j = 1 to 14; 
         set original_dates point = j; 
         output_dates = dates + &buffer.; 
         output; 
      end; 
   end; 
   stop;
run;

When you use point= on a set statement, you need to include a stop statement as well to prevent an infinite loop. Try this:
 
%let buffer = 3;     
data dates_with_buffer; 
   do i = -1*&buffer. to &buffer.; 
      do j = 1 to 14; 
         set original_dates point = j; 
         output_dates = dates + &buffer.; 
         output; 
      end; 
   end; 
   stop;
run;