How do i create a counter to decrease on variable change rules

[teelov]

THIS IS PERFECT!!!

i had no idea you can process first. twice

it turns out my mistake creating the counter in WANT actually helped.

Thank you

[Ksharp]

data have;
infile cards truncover;
input ID $	DATE_OF_VALUE :ddmmyy10.	VALUE	HAVE;
format DATE_OF_VALUE date9.;
cards;
109999999 05/12/2017 42376 1
109999999 05/12/2017 42376 2
109999999 13/12/2017 42521 1
109999999 13/12/2017 42521 2
109999999 19/03/2018 43395 1
109999999 19/03/2018 43395 2
109999999 19/03/2018 43395 3
109999999 19/03/2018 43395 4
109999999 04/06/2018 43953 1
109999999 04/06/2018 43953 2
109999999 17/09/2018 44899 1
109999999 17/09/2018 44899 2
;

proc sort data=have;
by id descending DATE_OF_VALUE;
run;

data want;
set have;
by id value notsorted;
temp+first.value; 
want=temp;
if not first.value then call missing(want);
drop temp;
run;

proc sort data=want;
by id DATE_OF_VALUE ;
run;

proc print;run;