gruop獲取表的最大值

Question

我是一種新的SQL，現在我試圖讓每個組（GRP）的最佳平均數，我有這張表。

Table1

我正在tryng得到這樣的事情，但林不知道該怎麼辦呢

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