data two;
  length id $1. var $2.;
  input id $ var $;
  cards;
1 21
2 23
3 24
4 25
5 27
6 2g
7 2k
run;
data three;
  length id $1. var $3.;
  input id $  var $;
  cards;
1 31a
2 35a
3 34a
4 350
8 370
9 3gv
0 3ks
run;
proc sort data=two; by id; run;
proc sort data=three; by id; run;
/*matched merges*/
data twothree;
  merge two three;
  by id;
run;
data threetwo;
  merge three two;
  by id;
run;
ods listing close;
ods chtml file="C:\outputdirectory\two.xls";
proc print data=two noobs;
title "dataset two";
run;
ods chtml file="C:\outputdirectory\three.xls";
proc print data=three noobs;
title "dataset three";
run;
ods chtml file="C:\outputdirectory\mergethreetwo.xls";
proc print data=threetwo noobs;
title "dataset threetwo:  produced by merge three two; by id;";
run;
ods chtml file="C:\outputdirectory\mergetwothree.xls";
proc print data=twothree noobs;
title "dataset twothree:  produced by merge two three; by id;";
run;
ods chtml close;
ods listing;

/*concatenation*/
%verifyVariablesSet(two,three)
data twothree;
  set two three;
run;
data threetwo;
  set three two;
run;
ods listing close;
ods chtml file="C:\outputdirectory\concatthreetwo.xls";
proc print data=threetwo noobs;
title "dataset threetwo:  produced by set three two;";
run;
ods chtml file="C:\outputdirectory\concattwothree.xls";
proc print data=twothree noobs;
title "dataset twothree:  produced by set two three;";
run;
ods chtml close;
ods listing;
 
/*interleaving*/
data twothree;
  set two three;
  by id;
run;
data threetwo;
  set three two;
  by id;
run;
ods listing close;
ods chtml file="C:\outputdirectory\interleavthreetwo.xls";
proc print data=threetwo noobs;
title "dataset threetwo:  produced by set three two; by id;";
run;
ods chtml file="C:\outputdirectory\interleavtwothree.xls";
proc print data=twothree noobs;
title "dataset twothree:  produced by set two three; by id;";
run;
ods chtml close;
ods listing;