You can use the following methods to add row numbers to a dataset in SAS:

Method 1: Add Row Number

data my_data2;
    row_number = _N_;
    set my_data1;
run;

Method 2: Add Row Number by Group

/*sort original dataset by var1*/
proc sortdata=my_data1;
    by var1;
run;

/*create new dataset that shows row number by var1*/
data my_data2;  
    set my_data1;
    by var1;
    if first.var1 then row_number=0;
    row_number+1;
run;

The following examples show how to use each method with the following dataset in SAS:

/*create dataset*/
data my_data1;
    input team $ points;
    datalines;
Mavs 22
Mavs 40
Rockets 41
Rockets 29
Rockets 30
Spurs 18
Spurs 22
Spurs 27
Warriors 13
Warriors 19
;
run;

/*view dataset*/
proc printdata=my_data1;

Example 1: Add Row Number

The following code shows how to add a new column called row_number that contains the row number for each observation:

/*create new dataset with column for row numbers*/
data my_data2;
    row_number = _N_;
    set my_data1;
run;

Notice that a new column called row_number has been added that contains the row number for each observation in the dataset.

Example 2: Add Row Number by Group

The following code shows how to add a row number by group:

/*sort original dataset by team*/
proc sortdata=my_data1;
    by var1;
run;

/*create new dataset that shows row number by team*/
data my_data2;  
    set my_data1;
    by var1;
    if first.var1 then row_number=0;
    row_number+1;
run;

Notice that the row numbers start over for each new team.

Additional Resources

The following tutorials explain how to perform other common tasks in SAS: