Date:         Mon, 7 Jul 2003 09:43:47 -0700
Reply-To:     "Huang, Ya" <yhuang@AMYLIN.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Huang, Ya" <yhuang@AMYLIN.COM>
Subject:      Re: Selecting Obs.
Comments: To: Franz <franz_cl2003@YAHOO.FR>
Content-Type: text/plain; charset="iso-8859-1"

How about sql?

DATA clinic;
  INPUT subid 3. l_intake
  ddmmyy10. visit_dt ddmmyy10.;
  FORMAT l_intake visit_dt date9.;
CARDS;
001 01062003 12062003
001 01062003 14062003
001 01062003 20062003
002 01052003 09052003
002 01052003 16052003
003 05052003 13052003
;
RUN;

proc sql;
select *
from clinic
group by subid
having abs(l_intake+13-visit_dt)=min(abs(l_intake+13-visit_dt))
;
-------------------
   subid   l_intake   visit_dt
ffffffffffffffffffffffffffffff
       1  01JUN2003  14JUN2003
       2  01MAY2003  16MAY2003
       3  05MAY2003  13MAY2003

If there is a tie, it will pick up both of them,
if you can define a rule for breaking up the tie,
I may try to add something in the code.

Kind regards,

Ya Huang

-----Original Message-----
From: Franz [mailto:franz_cl2003@YAHOO.FR]
Sent: Monday, July 07, 2003 9:27 AM
To: SAS-L@LISTSERV.UGA.EDU
Subject: Selecting Obs.


Dear all,

I have the following situation:


DATA clinic;
  INPUT subid 3. l_intake
  ddmmyy10. visit_dt ddmmyy10.;
  FORMAT l_intake visit_dt date9.;
CARDS;
001 01062003 12062003
001 01062003 14062003
001 01062003 20062003
002 01052003 09052003
002 01052003 16052003
003 05052003 13052003
;
RUN;


Out of the previous dataset (clinic) I would like
to select only one observation per subid according
to the following conditions:

* If the the patient have only one observation then
  this Observation must be selected.
* If he has more than one observation (the case
  with subid 001 and 002) then I must select the
  observation where the visit date (visit_dt) is
  much closer to the last intake date +14
  (l_intake +14)

This means, my final dataset should only have these
3 observations.

001 01062003 14062003
002 01052003 16052003
003 05052003 13052003

Thank you very much!
Regards,
Franz.


__________________________________
Do you Yahoo!?
SBC Yahoo! DSL - Now only $29.95 per month!
http://sbc.yahoo.com