I am working in PROC SQL to obtain a cumulative sum. My code currently reads:
PROC SQL;
CREATE TABLE WorkingFile2 AS
SELECT *,
(SELECT SUM(B.value)
FROM WorkingFile1 AS B
WHERE B.ID = A.ID
AND MDY(B.MONTH, 1, B.YEAR) <= MDY(A.MONTH, 1, A.YEAR)) AS SUM
FROM WorkingFile1 AS A | |
ORDER BY A.ID, A.YEAR, A.MONTH; |
QUIT;
I would like for the cumulative sum to restart when it reaches a positive value.
ID | Year | Month | Value | Sum | Desired Sum |
---|---|---|---|---|---|
12345 | 2013 | 5 | -94.32 | -94.32 | -94.32 |
12345 | 2013 | 6 | 19.82 | -74.5 | -74.5 |
12345 | 2013 | 7 | 55.49 | -19.01 | -19.01 |
12345 | 2013 | 8 | 28.73 | 9.72 | 9.72 |
12345 | 2013 | 9 | -24.6 | -14.88 | -24.6 |
12345 | 2013 | 10 | -36.4 | -51.28 | -61 |
How can I obtain the desired sum? This requires the cumulative sum to reset based upon its current value.
SQL is not the proper tool to do sequential operations such as cumulative sums. Use a datastep instead, it will be simpler and much faster.
data have;
input ID Year Month Value;
datalines;
12345 2013 5 -94.32
12345 2013 6 19.82
12345 2013 7 55.49
12345 2013 8 28.73
12345 2013 9 -24.6
12345 2013 10 -36.4
;
proc sort data=have; by id year month; run;
data want;
set have; by id;
if first.id or sum>0 then sum=0;
sum + value;
run;
proc print data=want noobs; run;
PG
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