How do I create a cumulative total column subset by another variable?

[Lamia]

thank you very much, the code worked perfectly, can you explain me please what is the use of drop c for the original dataset, and retain for the output one?

also why this instuction: put first.id last.id; ?

thank you 

[vijaylaxmi]

Using Drop C is the main trick here. What is does is it will drop that column when creating dataset.

Try this

Data ratings1;

set ratings(drop = C);

run;

Ratings1 will have all variable apart from C.

Retain C. What this statement does it,

1 it will not reinitialize value of C to missing on reading new observation,

2 remember value from previous obsevration.

Try reading some sas paper for more on retain statement, it pretty powerful statement.

put first.id last.id;

well this statement is not needed, I was just trying out something. You can remove this statement and program will work just fine. Main purpose of put is in debugging, it will write/print values in log for reach observation.

[Lamia]

thanks alot, it helps alot