Getting the max value of a table by gruop

Question

i'm kind of new in sql, right now I'm trying to get the best average for each group(GRP) and i have this table.

Table1

i'm tryng to get something like this, but im not sure how to do it

expected table

Answer 1

select  *
from    (
        select  dense_rank() over (partition by grp order by g_avg desc) as rn
        ,       *
        from    (
                select  sid
                ,       grp
                ,       first
                ,       last
                ,       avg(points) as g_avg
                from    YourTable
                group by
                        sid
                ,       grp
                ,       first
                ,       last
                )
        )
where   rn = 1