question about selectively removing duplicates

[ChrisNZ]

That's over-optimistic I reckon. An updated message and documentation is all we'll get.

[Astounding]

Here's a version that works when you have many variables, not just 2 or 3:

proc sort data=have;

by case_id state;

run;

data want;

update have (obs=0) have;

by case_id;

run;

It also works when you have many observations per CASE_ID.

[PGStats]

@Astounding, you may end up with unwanted results with UPDATE

data have;
input case_id state1 $ state2 $;
datalines;
1 A .
1 . .
1 . B
;

proc sort data=have;
by case_id state1 state2;
run;

data want;
update have (obs=0) have;
by case_id;
run;

proc print; run;

                         Obs    case_id    state1    state2

                          1        1         A         B

[Astounding]

@PGStats, you're right about the possibility of complications.  But it's difficult to tell what is really necessary here.  The original post is likely to be a simplification of the actual scenario so I wanted to make sure the UPDATE program was at least considered.  The example that you posted might actually be a desirable result ... it's up to the original poster to decide.

Note that I had the data set sorted by STATE so that non-missing-values the non-missing STATE observation would prevail if there is a conflict.