Count the same observations in two datasets

[dapenDaniel]

Hi SAS Masters,

I have two dataset. Have1 has 293 observations and Have2 has 246 observations. Both of them only have one variable called "base". I am wondering how many of them are shown in both datasets. I have sorted these two datasets by base. The code I used is below.

data common;
merge have1(in=h1) have2(in=h2);
by base;
if h1 and h2 then output common;
run;

however, the number of observations in "Common" is 258, which is more than the number of observations in Have2 (258 > 246). Did I use the wrong code? Thanks.

[novinosrin · Accepted solution]

Hi @dapenDaniel  That means one of the datasets has duplicate values of the same causing one to many join

[novinosrin]

Consider this example to help you understand better

data one;
input var;
cards;
1
2
3
;

data two;
input var;
cards;
1
1
2
2
2
3
;

data want;
 merge one two;
 by var;
run;

[dapenDaniel]

Thanks, @novinosrin