Recursive Query

[Patrick]

And yet another hash variation.

data want(drop=_: rename=(cust_id=Expected_cust_id p_cust_id=cust_id));
  if _n_=1 then
    do;
      dcl hash h1(dataset:'have(where=(not missing(p_cust_id)))' );
      h1.defineKey('p_cust_id');
      h1.defineData('cust_id');
      h1.defineDone();
    end;
  set have(where=(not missing(p_cust_id)));
  output;
  /* lookup children, counter loop added to avoid endless loops in case of DQ issues */
  do _i=1 to 10000 while(h1.find(key:cust_id)=0);
    output;
  end;
  if _i>=10000 then 
    do;
      putlog "DQ issues found leading to endless loop";
      putlog "Source record is: " _n_ 10. -l;
    end;
run;

[IvyHeng88]

Thank you so much @PGStats, awesome simple and straight forward ^_^