Assign as value of a variable the output of a proc summary

Question

I have a data set and I performed the following:

proc means data=mydata sum;
   var weight;
   output out=all 
   sum=overall;
 run;

Now, I would like to "copy" the value of "sum", in another proc that is the following as the value of new_weight:

    data test;
       if 0 then set test;
          if _n_=1 then 
      do;
     YEAR=2015;
     HOSPITAL="A";
     COUNTRY=.;
     new_weight="I need to add the value of sum from proc means as above";
  output;
  end;
  set db;
 output;
run;

I don't want to copy manually the value of the "sum" variable because it will take different values every time.

Answer 1

if _n_ eq 1 then set overall;;