Assignments of visit number based on date

[abc44]

Hi all, 

I have a relatively simple task I need some help with. 

I would like to assign a visit # to assessments that were performed on different dates for the same subject ID. Does someone know how I can generate this 3rd column called visit? 

ID    Date             Visit

1     01/02/2018     1

1     01/02/2018     1

1     01/02/2018     1

1     01/02/2018     1

1     08/08/2018     2

1     08/08/2018     2

1     08/08/2018     2

2     04/03/2018     1

2     04/03/2018     1

2     04/03/2018     1

2     09/09/2018     2

2     09/09/2018     2

etc. 

I basically need to assign a visit number per date within each subject ID, but am struggling with the code. 

I look forward to your feedback!
Thanks in advance!

[novinosrin · Accepted solution]

data want;
set have;
by id date ;
if first.id then visit=1;
else if first.date then visit+1;
run;

[abc44]

This works- thanks so much!

[novinosrin]

a teaser fun i learned from genius PD's dazzle playing with  PDV . Don't use this, but play with it. It's a joy as it gives an intuition of how DOW works 🙂

data want1;
if 0 then set have;
visit=0;
do until(last.id);
visit+1;
do until(last.date);
set have;
by id date;
output;
end;
end;
run;