Count amount within an year - sas

Question

I have a dataset which looks like
ID STATUS YEAR AMOUNT DT_1
. OPEN 2010 12 12
. OPEN 2009 24 10
. OPEN 2008 32 1
AA CLOSE 2015 150 12
AA CLOSE 2014 200 10
AA CLOSE 2010 10 8
AA CLOSE 2009 20 7
AA CLOSE 2008 18 5
AA OPEN 2012 21 8
AA OPEN 2001 20 7
AA OPEN 2000 18 5
Column DT_1 may take from a max of 12 to a min of 1.
I would like to calculate how much amount there is within this range each time. This means that I should assign to the current year the previous amount.
I would like to expect something like this
ID STATUS YEAR AMOUNT DT_1
. OPEN 2010 12 24
. OPEN 2009 24 32
. OPEN 2008 32 .
AA CLOSE 2015 150 200
AA CLOSE 2014 200 10
AA CLOSE 2010 10 20
AA CLOSE 2009 20 18
AA CLOSE 2008 18 .
AA OPEN 2012 21 20
AA OPEN 2001 20 18
AA OPEN 2000 18 .
I have tried as follows
proc sql;
create table tab1 as
select ID, status, year, sum(amount) as tot_amount, dt_1
from tab
group by 1,2,3;
quit;
but it does not give me the expected output.
EDIT: I had to edit the question as the expected output was different.

Answer 1

So DT_1 is the amount form the previous year? If so it would be a lot easier if the data was sorted by increasing value of YEAR, instead of decreasing as displayed in the question. Then you can just use the LAG() function.
proc sort data=HAVE out=WANT ;
by id status year ;
run;
data WANT;
set want ;
by id status year;
dt_1 = lag(amount);
if first.status then dt_1=.;
run;

Answer 2

See if this is what you want
data have;
input ID $ STATUS $ YEAR AMOUNT;
datalines;
. OPEN 2010 12
. OPEN 2009 24
. OPEN 2008 32
AA CLOSE 2015 150
AA CLOSE 2014 200
AA CLOSE 2010 10
AA CLOSE 2009 20
AA CLOSE 2008 18
AA OPEN 2012 21
AA OPEN 2001 20
AA OPEN 2000 18
;
data want(drop = s);
merge have
have(firstobs = 2 keep = amount STATUS
rename = (amount = DT_1 STATUS = s));
if STATUS ne s then DT_1 = .;
run;