選擇最高金額排

Question

我有下面的表：

Categorie 
Rubriek 
Adv_nr 

對於每個rubriek很可能有100分以上的adv_nr的。

我想從每個rubriek中選擇最多5行，這可能在一個查詢中嗎？

Answer 1

select * from table as t1 
where (select count(*) from table as t2 
     where t1.rubriek = t2.rubriek and t2.adv_nr > t1.adv_nr) < 5 
order by rubriek,adv_nr desc 

Answer 2

select * from *ad_table* 
    where category_id IN ( 
     select *category_table*.id 
      from *category_table*, *group_table* 
      where *category_table*.id = *group_table*.category_id) 
    LIMIT 5;