SAS hash table - multivalues for single key and find_next - hash

Question

I am using a hash table to look up values and determine whether there is a match. These are the testing codes.
What I am trying to do is to check whether students in roster have entries in grade_roster; if a student has entries in grade_roster, I attach that grade_on_report to a new dataset that is the dup of roster.
name is my key and the grades are values. One name may have several grades, i.e. multivalues for a single key. I was able to find all names in the roster that have a match in grade_roster using find_next(), but I could not attach the right grade to the new dataset.
It seems like whenever find_next() is called, the value for the key was set to the next item in the list, and therefore assign that value to all previous keys.
Here is my code:
data roster;
input name $ course $ grade_on_paper $;
datalines;
Mary English A
Mary German B
Josh English B
Lily Spanish B
Lucy Physics C
John Music A
Eric Math A
Eric Music B
;
run;
data grade_roster;
input name $ course $ grade_on_report $;
datalines;
Mary English A
Mary German B
John Music A
Eric Math A
Eric Music B
;
run;
data assign_grade;
set roster;
format grade_on_report $1.;
declare hash ht1(dataset:"grade_roster", multidata:"Y");
ht1.defineKey("name");
ht1.defineData("grade_on_report");
ht1.defineDone();
rc = ht1.find();
do while(rc = 0);
rc = ht1.find_next();
end;
run;
What I got was this:
name course grade_on_paper grade_on_report name_found
1 Mary English A B Y
2 Mary German B B Y
3 Josh English B
4 Lily Spanish B
5 Lucy Physics C
6 John Music A A Y
7 Eric Math A B Y
8 Eric Music B B Y
What I want is:
name course grade_on_paper grade_on_report name_found
1 Mary English A A Y
2 Mary German B B Y
3 Josh English B
4 Lily Spanish B
5 Lucy Physics C
6 John Music A A Y
7 Eric Math A A Y
8 Eric Music B B Y
Note: name and course together are not unique identifiers. It seems like they are unique identifiers in this particular test code but they are not unique identifiers in the actual dataset I am working on. The goal is to use name as the only key in ht1.defineKey() and get the correct result.
Any help would be appreciated. Thank you!

Answer 1

If you are trying to find data on a specific student and course, you need to make both name and course part of the key.
data assign_grade;
set roster;
format grade_on_report $1.;
declare hash ht1(dataset:"grade_roster", multidata:"Y");
ht1.defineKey("name", "course");
ht1.defineData("grade_on_report");
ht1.defineDone();
rc = ht1.find();
do while(rc = 0);
rc = ht1.find_next();
end;
run
I tested this on sligthly different data
data roster;
input name $ course $ grade_on_paper $;
datalines;
Mary English A
Mary German B
Josh English B
Lily Spanish B
Lucy Physics C
John Music A
Eric Math A
Eric Music B
;
run;
data grade_roster;
input name $ course $ grade_on_report $;
datalines;
Mary German B
Mary English A
John Music A
Eric Math C
Eric Music B
;
run;
and got what I expected.