select observations

[deleted_user]

I have more observations for the same subject, what i want to do is select only subjects with one observetion. How can I do this?
dataset is similar to this:
id blood pressure
1 130
2 120
3 140
3 160
3 125
4 120
4 135
4 130

i want only subjects with one misuration i.e subject number 1 and 2 in this example
thank you

[yonib]

Hi ,
There are several ways of doing it ,
For example :

data temp;
input id blood_pressure;
cards;
1 130
2 120
3 140
3 160
3 125
4 120
4 135
4 130
;
run;
proc sql;
create table temp2 as
select b.*
from(

select count(id) as count
,id
from temp
group by id
having count(id)=1
) as a
join temp as b
on a.id=b.id;
quit;

[Flip]

proc sort;
by id bld_pres;
run;

data new;
set old;
by id bld_pres;
if first.id and last.id;
run;