How to get only one row per person?

[peter michaux]

Hi,

I would like to have a table of people and the grades they achieved on a test. They may take the test multiple times. For example

Table: Marks
Fields: Person Grade
A 90
B 62
C 23
C 69
B 81

I'd like to make a query that will list the highest grade each person got. The results would be

Person Grade
A 90
B 81
C 69

Do I need both "order by" and "group by" to do this? If you know the query please give me some hints!

Thanks,
Peter