The following program prints a subset of the observations in the ICDB Study's background (back), pain and urgency (purg), and family history (fhx) data sets:

LIBNAME icdb 'C:\yourdrivename\Stat481WC\04combineII\sasndata';
PROC PRINT data = icdb.back (OBS=5) NOOBS;
        title 'The back data set';
RUN;       
PROC PRINT data = icdb.purg (OBS=5) NOOBS;
        title 'The purg data set';
                    where v_type = 0;
RUN;        
PROC PRINT data = icdb.fhx (OBS=5) NOOBS;
        title 'The fhx data set';
RUN;

Output

In each case, the PRINT procedure's OBS=5 option tells SAS to print just the first five observations of each data set. The second PRINT procedure contains an extra direction to SAS to print only those observations for which the v_type variable equals 0. Before you can run the program, you'll need to right-click the data set links... back, purg, and fhx... so that you can save the data sets to a convenient location on your computer. After doing so, launch the SAS program, and edit the LIBNAME statement so that it reflects the location in which you saved the data sets. Then, run   the program, and review the output so that you can familiarize yourself with each data set.

As you can see, the data sets share three variables — subj, v_type, and v_date, and then each data set has its own set of unique variables. Our interest in this example is to merge the three data sets into a new data set called icdbdata that contains the common subj variable, the b_date and sex variables from the back data set, the purg_1 and purg_2 variables from the purg data set, and the fhx_1 and fhx_2 variables from the fhx data set. That is, when all is said and done, this is what the first ten observations of the icdbdata set should look like:

The following code does the trick for us:

LIBNAME icdb 'C:\yourdrivename\Stat481WC\04combineII\sasndata';
DATA icdbdata (drop = v_type);
   merge icdb.back (keep = subj b_date sex)
           icdb.purg (where = (v_type = 0)
                      keep = subj v_type purg_1 purg_2)
           icdb.fhx  (keep = subj fhx_1 fhx_2);
   by subj;
RUN;
PROC PRINT data = icdbdata (OBS = 10) NOOBS;
        title 'The icdbdata data set';
RUN;

Output