Base SAS certificate sample: merge and in

Question

What is the right selection for this problem and why? Thanks:

---

Given the SAS data set WORK.EMP_NAME:

  Name  EmpID
  ----  -----
  Jill   1864
  Jack   2121
  Joan   4698
  John   5463

Given the SAS data set WORK.EMP_DEPT:

  EmpID  Department
  -----  ----------
   2121  Accounting
   3567  Finance
   4698  Marketing 
   5463  Accounting

The following program is submitted:

 data WORK.ALL;
     merge WORK.EMP_NAME(in=Emp_N) 
           WORK.EMP_DEPT(in=Emp_D);
     by Empid; 
     if (Emp_N and not Emp_D) or (Emp_D and not Emp_N);
 run;

How many observations are in data set WORK.ALL after submitting the program? A. 1 B. 2 C. 3 D. 5

Answer 1

Answer will be B.2 2 observations with 3 variables already, so new dataset ALL will have observations what are not neither in EMP_NAME or EMP_DEPT column EmpID . Library actually is WORK for all.

This statement does show that to merge only observations that are not common/present in EmpID when merging. Emp_N is from first dataset and Emp_D is from second dataset.

by Empid; 
 if (Emp_N and not Emp_D) or (Emp_D and not Emp_N); 

Hope it helps with the details bellow:

 title "stackoverflow merge EMP_DEPT";
data work.EMP_NAME;
input Name $ EmpID;
datalines;
Jill   1864
Jack   2121
Joan   4698
John   5463
;
run;


proc print data = work.EMP_NAME;
run;


title "stackoverflow merge EMP_DEPT";
data work.EMP_DEPT;
 input EmpID  Department $ ;
 datalines;
2121  Accounting
3567  Finance
4698  Marketing 
5463  Accounting
;
run;

proc print data = work.EMP_DEPT;
run;


*merge;

data WORK.ALL;
 merge WORK.EMP_NAME(in=Emp_N) 
       WORK.EMP_DEPT(in=Emp_D);
 by Empid; 
 if (Emp_N and not Emp_D) or (Emp_D and not Emp_N);
 run;

 proc contents data=work.ALL;

 run;

 proc print data = work.ALL;
 run;