Obtain the latest collection date in Proc Freq or from extra Data steps?

[ybz12003]

I have a PROC FREQ code listed below in the frequency output dataset, CNT. I would like to obtain information for the latest collection date in the "Have" dataset. Is there a way to add a step in the PROC FREQ procedure, or do I need to add an extra data step and merge it with the output CNT data? Please help, thanks.

Proc freq data=Have noprint; 
	table  LabIDs*Test_Code*Match / nopercent nocol  out=CNT;
	where match in ('N');
run;

[mkeintz]

You do not provide enough information to answer your own question.

Mainly, what exactly do you mean by "collection date"?  Is it a variable in the dataset HAVE?  You specify three variables in HAVE (Labids, test_code, match), none of which suggest a collection date.

Is it the creation date of HAVE?

BTW, there is no need for the ** match" expression in the TABLE statement, since you allow only one match value,  i.e. where match in ('N').

Please clarify.

[ballardw]

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@ybz12003 wrote:

I have a PROC FREQ code listed below in the frequency output dataset, CNT. I would like to obtain information for the latest collection date in the "Have" dataset. Is there a way to add a step in the PROC FREQ procedure, or do I need to add an extra data step and merge it with the output CNT data? Please help, thanks.

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You ask "for the latest collection date in the "Have" dataset" but your code is getting counts by LabIds and Test_code. So should that request be "for the latest collection date in the "Have" for each LabIds and Test_code combination in the dataset"? Quite a bit different things.

If you want latest date for each combination of LabIds and Test_code AND have a collection date variable one way AND that the sort order for the collection date variable sorts in date order (i.e and an actual SAS date value or a YYYYMMDD value) the following should work.

Proc freq data=Have noprint; 
	table  LabIDs*Test_Code*collectiondate*Match / nopercent nocol  out=CNT;
	where match in ('N');
run;

data want;
   set count;
   by Labids test_code;
   if last.test_code;l
run;

[ybz12003]

The Collection_Date volume (mmddyy10.) is in the "Have" dataset, but not in the CNT frequency output dataset.