Only keep matching values

[jcapua2]

I have a dataset with patient_type=living and patient_type=deceased, as well as a column for match_ID.

I want to keep only observations where patient_type=living and patient_type=deceased have the same match_ID, and exclude everything else.

For example,

Key     Px_Type   Match_ID

1115    L               0001a

1116    D              0001a

1117    D              0004b

1118    L               0003b

I want to keep observations 1115 (L) and 1116 (D) since they have the same match_ID. Is there a way to approach this in SAS?

[RW]

If your data is sorted then you could try a statement like this

if compress(Match_ID) eq lag(compress(Match_ID)) and compress(Px_Type) in ( "D","L") then output ;

[ballardw]

Is there other data that has to be preserved? If so, what exactly would the result look like?

[Ksharp · Accepted solution]

data have;
input Key     Px_Type $  Match_ID $;
cards;
1115    L               0001a
1116    D              0001a
1117    D              0004b
1118    L               0003b
;
run;

proc sql;
select *
 from have
  group by  Match_ID
   having count(distinct  Px_Type) ne 1;
quit;