Getting rid of blanks

[Ksharp]

data have;
  input ID   Alteration $    Mutation $;
  cards;
1      .         ART
1      .         COX
2      GBR       LIR
2      ART       EGF
3      LOP        .
3      ART       NIH
3      .         EGF
4      .         ART
4      .         COX
;
proc sql;
select *
 from have
  group by id
   having n(Alteration) ne 0 and n(Mutation) ne 0;
quit;