how to get first obs value of start date and last obs value of end date where multiple obs present

[knveraraju91]

Dear,

In my data, each subject has startdate(sdate) enddate(edate) of dose of a drug taken. For the derivation an variable I need an output dataset with first.sdate of each subject and last.edate of each subject. Thank you

output need;

id           sdate                    edate

1            05OCT2015         30OCT2015

2            05OCT2015         29OCT2015

3            06OCT2015         25OCT2015

data one;
input id sdate  edate date9.
datalines;
1 05OCT2015 06OCT2015
1 06OCT2015 17OCT2015
1 17OCT2015 30OCT2015
2 05OCT2015 10OCT2015
2 11OCT2015 20OCT2015
2 20OCT2015 25OCT2015
2 26OCT2015 29OCT2015
3 06OCT2015 17OCT2015
3 17OCT2015 25OCT2015
;

[novinosrin]

data one;
input id sdate : date9. edate :date9.;
format sdate edate date9.;
datalines;
1 05OCT2015 06OCT2015
1 06OCT2015 17OCT2015
1 17OCT2015 30OCT2015
2 05OCT2015 10OCT2015
2 11OCT2015 20OCT2015
2 20OCT2015 25OCT2015
2 26OCT2015 29OCT2015
3 06OCT2015 17OCT2015
3 17OCT2015 25OCT2015
;

data want;
set one;
by id;
retain _sdate;
if first.id then _sdate=sdate;
else if last.id then sdate=_sdate;
if last.id;
drop _sdate;
run;

Regards,

Naveen Srinivasan

[user24feb]

Try:

Proc SQL;
  Create Table Want As
    Select id,
	  Min(sdate) as sdate Format=Date9.,
	  Max(edate) as edate Format=Date9.
    From one
    Group By id;
Quit;

[ballardw]

If there are no other variables involved:

proc summary data=have nway;

   class id;

   var sdate edate;

   ouput out=want(drop= _:) min(sdate)= max(edate)=;

run;