Finding redundant entries for same ID and date

[mcdj]

Hi there,I have longitudinal data in long format. each individual (part of a couple) is supposed to have a single row per visit. there are some, like below, that have 2 entries for an individual on the same date. I need to find out which IDs and for which visitdates there are multiple rows/entries. Help? Thanks!

Obs	id	htid	womanage	manage	cjbase	visitdate	linked	inflam_3mo_female
1244	5538M	5538	22	35	+-	05NOV2003	1	.
1245	5538F	5538	22	35	+-	05NOV2003	1	1
1246	5538F	5538	22	35	+-	05NOV2003	1

[mohamed_zaki]

proc sort data=have out=havesorted;
by id visitdate;
run;
data want ;
set havesorted ;
by id visitdate;
if not (first.visitdate and last.visitdate) then output;
run;

[LinusH · Accepted solution]

If you wish to output all observations in a duplicate situation, you can use SQL as well (untested):

proc sql;
   create table want as
      select *
      from have
      group by id, visitdate
      having count(*) > 1
   ;
quit,

If you just wish to output the duplicate observation(s), use proc sort with the dupout= option.

[ballardw]

And yet another possibility

proc freq data=have noprint;

   tables Id*visitdate/list out=dups (where=(count>1));

run;

[mcdj]

thanks, worked perfectly!