How to merge two calculated datasets in SAS EG?

[Andalusia]

I have a dataset (example) which looks like this:

data have;
  infile datalines truncover;
  input type $ quarter phase counter percent;
  datalines;
BB-B 202001 1 94 13
BB-B 202001 2 91 2
BB-B 202001 3 50 2
BB-B 202002 1 10 11
BB-B 202002 2 20 4
BB-B 202002 3 5 4
BB-B 202003 1 10 1
BB-B 202003 2 20 3
BB-B 202003 3 7 3
BB-B 202004 1 10 1
BB-B 202004 2 20 3
BB-B 202004 3 7 3
BB-B 202101 1 10 1
BB-B 202101 2 20 3
BB-B 202101 3 7 3
AA-C 202001 1 67 6
AA-C 202001 2 38 4
AA-C 202001 3 68 4
AA-C 202002 1 29 6
AA-C 202002 2 38 4
AA-C 202002 3 89 4
AA-C 202003 1 20 6
AA-C 202003 2 39 4
AA-C 202003 3 105 4
AA-C 202004 1 15 6
AA-C 202004 2 36 4
AA-C 202004 3 95 4
AA-C 202101 1 27 6
AA-C 202101 2 45 4
AA-C 202101 3 98 4
;

Im using below code to calculate the mean and the stdev based on the last 4 quarters, this works perfect.

%let n_quarters = 4;

proc sort data=have;
by type phase quarter;
run;

data extract;
counta = 0;
do until (last.phase);
  set have;
  by type phase;
  counta + 1;
end;
countb = 0;
do until (last.phase);
  set have;
  by type phase;
  countb + 1;
  if countb gt (counta - &n_quarters.) then output;
end;
drop counta countb;
run;

proc summary data=extract;
by type phase;
var counter;
output out=want (drop=_type_ _freq_) mean()=mean std()=std;
run;

I want to keep those mean and std and kind of merge the previous two datasets(want & extract). I would like to have a new dataset which looks like this:

type	quarter	phase	counter	percent	mean	std
AA-C	202002	1	29	6	22,75	6,448514041
AA-C	202003	1	20	6	22,75	6,448514041
AA-C	202004	1	15	6	22,75	6,448514041
AA-C	202101	1	27	6	22,75	6,448514041
AA-C	202002	2	38	4	39.5	3,8729833462
AA-C	202003	2	39	4	39.5	3,8729833462
AA-C	202004	2	36	4	39.5	3,8729833462
AA-C	202101	2	45	4	39.5	3,8729833462
AA-C	202002	3	89	4	96.75	6,6520673478
AA-C	202003	3	105	4	96.75	6,6520673478
AA-C	202004	3	95	4	96.75	6,6520673478
AA-C	202101	3	98	4	96.75	6,6520673478
BB-B	202002	1	10	11	10	0
BB-B	202003	1	10	1	10	0
BB-B	202004	1	10	1	10	0
BB-B	202101	1	10	1	10	0
BB-B	202002	2	20	4	20	0
BB-B	202003	2	20	3	20	0
BB-B	202004	2	20	3	20	0
BB-B	202101	2	20	3	20	0
BB-B	202002	3	5	4	6.5	1
BB-B	202003	3	7	3	6.5	1
BB-B	202004	3	7	3	6.5	1
BB-B	202101	3	7	3	6.5	1

[Kurt_Bremser · Accepted solution]

Add a final MERGE step to your code:

proc summary data=extract;
by type phase;
var counter;
output out=want1 (drop=_type_ _freq_) mean()=mean std()=std;
run;

data want2;
merge
  have
  want1 (in=e)
;
by type phase;
if e;
run;