Compare rows within group of size two - sas

Question

I've got the below code that works beautifully for comparing rows in a group when the first row doesnt matter.
data want_Find_Change;
set WORK.IA;
by ID;
array var[*] $ RATING;
array lagvar[*] $ zRATING;
array changeflag[*] RATING_UPDATE;
do i = 1 to dim(var);
lagvar[i] = lag(var[i]);
end;
do i = 1 to dim(var) ;
changeflag[i] = (var[i] NE lagvar[i] AND NOT first.ID);
end;
drop i;
run;
Unfortunately, when I use a dataset that has two rows per group I get incorrect returns, I'm assuming because the first row has to be used in the comparison. How can I compare the only to rows and a return only on the second row. This did not work:
data Change;
set WORK.Two;
by ID;
changeflag = last.RATING NE first.RATING;
run;
Example of the data I have and want
Group Name Sport DogName Eligibility
1 Tom BBALL Toto Yes
1 Tom golf spot Yes
2 Nancy vllyball Jimmy yes
2 Nancy vllyball rover no
want
Group Name Sport DogName Eligibility N_change S_change D_Change E_change
1 Tom BBall Toto Yes 0 0 0 0
1 Tom golf spot Yes 0 1 1 0
2 Nancy vllyball Jimmy yes 0 0 0 0
2 Nancy vllyball rover no 0 0 1 1

Answer 1

If you want only the first row to not be flagged, you first need to create a variable enumerating the rows within each group. You can do so with:
data temp;
set have;
count + 1;
by Group;
if first.Group then count = 1;
run;
In a second step, you can run a proc sql with a subquery, count distinct by groups, and case when:
proc sql;
create table want as
select
Group, Name, Sport, DogName, Eligibility,
case when count_name > 1 and count > 1 then 1 else 0 end as N_change,
case when count_sport > 1 and count > 1 then 1 else 0 end as S_change,
case when count_dog > 1 and count > 1 then 1 else 0 end as D_change,
case when count_E > 1 and count > 1 then 1 else 0 end as E_change
from (select *,
count(distinct(Name)) as count_name,
count(distinct(Sport)) as count_sport,
count(distinct(DogName)) as count_dog,
count(distinct(Eligibility)) as count_E
from temp
group by Group);
quit;
Best,