Create and classify a row based on column values - sql

Question

I am attempting to assign a classification to a row of data based on whether certain values exist. Utilizing the sample code below I have gotten to a place where I've gotten stuck.
proc sql;
create table test
(id char(4),
task char(4),
id2 char(4),
status char(10),
seconds num);
insert into test
values('1','A','1','COMP',15)
values('1','B','2','WORK',20)
values('1','C','3','COMP',50)
values('1','D','3','COMP',null)
values('2','A','1','COMP',15)
values('2','B','2','COMP',520)
values('2','C','2','COMP',NULL)
values('2','D','3','COMP',221)
values('2','E','3','COMP',null)
values('2','F','3','COMP',null);
proc sql;
create table test2 as
select
ID,
ID2,
STATUS,
SUM(SECONDS) AS SECONDS,
sum(case when task='A' THEN 1 ELSE 0 END) AS A,
sum(case when task='B' THEN 1 ELSE 0 END) AS B,
sum(case when task='C' THEN 1 ELSE 0 END) AS C,
sum(case when task='D' THEN 1 ELSE 0 END) AS D,
sum(case when task='E' THEN 1 ELSE 0 END) AS E,
sum(case when task='F' THEN 1 ELSE 0 END) AS F
from
test
GROUP BY
ID,
ID2,
STATUS
;
quit;
Ultimately I would like to classify each row that gets created in the second step 'test2' to have a column that looks to the values in each lettered column(A-F) and Label them as such. So when the Row has a 1 in Column A only, it would be labeled 'A' but when a row has a 1 in multiple columns like 'D', 'E' and 'F' I would like it to be labeled as D_E_F.

Answer 1

Best way to do this is in a DATA STEP:
data test3;
format classifier $32.;
set test2;
array vars[6] A B C D E F;
classifier = "";
do i=1 to 6;
if vars[i] then
classifier = catx("_",classifier,vname(vars[i]));
end;
drop i;
run;
I create a character variable CLASSIFIER with length 32.
I define an array that groups the columns A through F. This allows me to loop over those columns easily.
Initialize the CLASSIFIER variable.
Loop over the array. If the value =1, then add the name of the variable to the CLASSIFIER string.
CATX(delim,str1,str2) concatenates str1 and str2 with the delim in the middle. It also removes whitespace.
VNAME(array[i]) returns the variable name of the variable pointed to by array[i].
Finally remove the i loop variable, unless you really want it in your output.

Answer 2

I know it is ugly, but you can do it with CASE statements accumulating the wanted result in another field. You have the SQL Fiddle here.
Note that if it is possible that the concatenation is empty you will have to check this condition to avoid performing the substring.
select
ID,
ID2,
STATUS,
SUM(SECONDS) AS SECONDS,
sum(case when task='A' THEN 1 ELSE 0 END) AS A,
sum(case when task='B' THEN 1 ELSE 0 END) AS B,
sum(case when task='C' THEN 1 ELSE 0 END) AS C,
sum(case when task='D' THEN 1 ELSE 0 END) AS D,
sum(case when task='E' THEN 1 ELSE 0 END) AS E,
sum(case when task='F' THEN 1 ELSE 0 END) AS F,
substring(
case when sum(case when task='A' THEN 1 ELSE 0 END) = 1 then '_A' else '' end
+ case when sum(case when task='B' THEN 1 ELSE 0 END) = 1 then '_B' else '' end
+ case when sum(case when task='C' THEN 1 ELSE 0 END) = 1 then '_C' else '' end
+ case when sum(case when task='D' THEN 1 ELSE 0 END) = 1 then '_D' else '' end
+ case when sum(case when task='E' THEN 1 ELSE 0 END) = 1 then '_E' else '' end
+ case when sum(case when task='F' THEN 1 ELSE 0 END) = 1 then '_F' else '' end,
2, len(case when sum(case when task='A' THEN 1 ELSE 0 END) = 1 then '_A' else '' end
+ case when sum(case when task='B' THEN 1 ELSE 0 END) = 1 then '_B' else '' end
+ case when sum(case when task='C' THEN 1 ELSE 0 END) = 1 then '_C' else '' end
+ case when sum(case when task='D' THEN 1 ELSE 0 END) = 1 then '_D' else '' end
+ case when sum(case when task='E' THEN 1 ELSE 0 END) = 1 then '_E' else '' end
+ case when sum(case when task='F' THEN 1 ELSE 0 END) = 1 then '_F' else '' end) - 1) as wantedOutput
from
test
GROUP BY
ID,
ID2,
STATUS