Selecting first record based on two groups?

Tpham — Fri, 12 Apr 2013 22:20:40 GMT

I have been trying to use the first/last commands for the last hour and trying to figure out how to get this to work.

I have the following sample lab data:

So as you noticed, each person may have multiple labs per year. I want to grab the first lab (by date) for each year for each person. So basically I want a table that looks like this:

So far, I have tried sorting it by ID and date created a dataset using first.date; but that didn't work.

I was wondering if someone can provide me with some help? I am pretty lost on how to do this!

Thanks!

Re: Selecting first record based on two groups?

PGStats — Sat, 13 Apr 2013 00:12:51 GMT

It's FIRST.YEAR that must be used, you want the first record (date) within each year :

proc sort data=sample; by id year date; run;

data want;
set sample; by id year;
if first.year;
run;

id	date	count	year
1	12/5/2007	< 75	2007
1	2/27/2008	500	2008
1	6/30/2008	< 75	2008
1	10/27/2008	< 75	2008
1	2/23/2009	900	2009
1	6/1/2009	< 75	2009
1	8/24/2009	< 75	2009
1	12/7/2009	< 75	2009
2	4/25/2007	77	2007
2	7/6/2007	< 75	2007
2	8/27/2007	< 75	2007
2	11/26/2007	< 75	2007
2	1/28/2008	< 75	2008
2	6/30/2008	< 75	2008
2	11/5/2008	< 75	2008
2	2/9/2009	< 75	2009
2	5/11/2009	< 75	2009
2	9/23/2009	< 75	2009
2	3/1/2010	< 75	2010

id	date	count	year
1	12/5/2007	< 75	2007
1	2/27/2008	500	2008
1	2/23/2009	900	2009
2	4/25/2007	77	2007
2	1/28/2008	< 75	2008
2	2/9/2009	< 75	2009
2	3/1/2010	< 75	2010

topic Re: Selecting first record based on two groups? in SAS Programming

Selecting first record based on two groups?

Re: Selecting first record based on two groups?