if condition

[Vijay77]

I need output only if below condition satisfies

Output if, Sample ID "Serum" is present in dataset A  and (COL) = NO or MISSING in the dataset B for same acc ID.
Populate NEW_VAR: Sample not collected in B

[andreas_lds]

Please post data in usable form and describe exactly the expected result.

[Patrick]

You need to help us help you by providing sample data (via a working SAS datastep), show the desired result and explain the logic to get from have to want.

The following code totally based on assumptions and untested.  ....and I won't answer any questions unless you provide at least sample data via a data step which I just can copy/paste into a code window and execute.

data want;
  if _n_=1 then 
    do;
      if 0 then set b(keep=acc_id col);
      dcl hash h1(dataset:'b(keep=acc_id col where=(col in (' ','NO')))');
      h1.defineKey('acc_id');
      h1.defineDone();
    end;

  set a;
  if sample_id='Serum' and h1.check()=0 then output;
run;