Retaining only last patient visit data

[fengyuwuzu]

I have data as below:

ID	visit	measure	Measure_Type
1	1	12	A
2	1	13	A
2	2	14	A
3	1	15	A
1	1	12	B
2	1	13	B
2	2	14	B
3	1	15	B
1	1	12	C
2	1	13	C
2	2	14	C
3	1	15	C

The ID 2 has two visits, and I only want to select the second visit and delete the first visit. I tried with the following code but it does not work:

data want;
set have;
by measure_type descending visit id;
if first.id;
run;

any hints? Thanks

[ballardw · Accepted solution]

First you would have to sort the data the same as the By statement you use.

But Since there are different values of visit then you wouldn't want the visit in the sort order then you may want to to use

by Measure_type id notsorted;

Then you would want to us IF LAST.ID.  If there is only one then the First and Last are the same record.

[Astounding]

I think you're looking in the right forest ... here's a variation.  First, sort if the data are not already in this order:

proc sort data=have;

by measure_type id visit;

run;

Then select the last visit for a given measure_type / id combination:

data want;

set have;

by measure_type id visit;

if last.id;

run;

[fengyuwuzu]

Thank you, both of you. Both worked.