/* Some simple merge and set commands  */
data a;
input x y z;
datalines;
1 3 7
2 4 8
1 4 10
2 1 6
;
run;
data b;
input x y zz;
datalines;
1 3 9
3 4 6
2 2 7
1 1 9
;
run;
proc sort data=a; by x;
proc sort data=b; by x;
run;
proc print data=a;
proc print data=b;
run;
/* The data sets are simply stacked; missing */
/* values are assigned to z and zz           */
data c; set a b;
proc print data=c;
run;
data cc; set a b; by x;
proc print data=cc;
run;
/* A merge wihtout a BY statement            */
/* Values from b overwrite values from a     */
data d; merge a b;
proc print data=a;
proc print data=b;
proc print data=d;
run;
/* Values from a overwrite values from b     */
data dd; merge b a;
proc print data=a;
proc print data=b;
proc print data=dd;
run;
/* There is only one true match-merge here   */
proc sort data=a; by x y;
proc sort data=b; by x y;
data f; merge a b; by x y;
proc print data=a;
proc print data=b;

proc print data=f; run;

/* Attempt at many-to-many merge.  Did not work well within the lecture. */
data ff; merge a b; by x; run; proc print data=ff; run;