Extract every last unique combination ordered by date

[lydiawawa]

I'm having difficulty in extracting unique tasks performed by workers in events arranged by time. The unique combination is defined by ID and Mode. Following dataset mimics the scenario :

 ID        Time       Mode     Event
 23456     20120101    A        Open
 23456     20120101    B        Closed
 87690     20120311    G        Closed
 98000     20120201    B        Open
 98000     20120301    A        Open
 98000     20120101    A        Open
 87889     20121009    C        Closed
 87889     20120101    C        Open
 87900     20120411    A        Closed
 87900     20120102    A        Closed

Hope for the following result:

 ID        Time       Mode     Event
 23456     20120101    A        Open
 23456     20120101    B        Closed
 87690     20120311    G        Closed
 98000     20120201    B        Open
 98000     20120301    A        Open
 87889     20121009    C        Closed
 87900     20120411    A        Closed

I will first sort by time in descending order:

  proc sort data=df; by ID descending time; run;

Then I can use sort again to get unique combo by ID and Mode:

  proc sort data=df dupout=nodup nodupkey;
     by ID Mode; run;

In the last step, how do I ensure that the none-duped record is also the latest event?

Thanks!

[novinosrin · Accepted solution]

data have;
input ID        Time :yymmdd10.       Mode  $   Event $;
cards;
 23456     20120101    A        Open
 23456     20120101    B        Closed
 87690     20120311    G        Closed
 98000     20120201    B        Open
 98000     20120301    A        Open
 98000     20120101    A        Open
 87889     20121009    C        Closed
 87889     20120101    C        Open
 87900     20120411    A        Closed
 87900     20120102    A        Closed
 ;

proc sql;
create table want as
select *
from have
group by id ,mode
having time=max(time)
order by id,time;
quit;

[lydiawawa]

Hi, Sorry I'm not with SAS. Just wondering, will this statement take care of duplicated combo of ID and mode? Thank you for the prompt reply! I think the first part of Sql arranges the data and the second part takes the latest date?

[novinosrin]

@lydiawawa  Please test the code and let us know. If it doesn;t meet your needs , let's rework to meet your requirement.  I can't claim anything from my side. I am hoping you test carefully and diligently. 

[PGStats]

Sort, then select last in by-group:

data have;
input ID Time :yymmdd10. Mode $ Event $;
format time yymmdd10.;
datalines;
 23456     20120101    A        Open
 23456     20120101    B        Closed
 87690     20120311    G        Closed
 98000     20120201    B        Open
 98000     20120301    A        Open
 98000     20120101    A        Open
 87889     20121009    C        Closed
 87889     20120101    C        Open
 87900     20120411    A        Closed
 87900     20120102    A        Closed
 ;

proc sort data=have; by ID mode time; run;

data want;
set have; by ID mode;
if last.mode;
run;

[ballardw]

FWIW you need to be very careful discussing and naming variables related to time, dates and datetime values appropriately when dealing with SAS. Your "time" variable appears to be a date value. The reason is time in SAS values is measured in seconds and dates are measured in days. If you search this forum you find a number of discussion about code not behaving properly that eventually boiled down to misunderstanding this basic SAS measurement difference and why results were much different than expected.