如何在给定的表中找到每个主题的前三名

您可以使用变量来执行此 *** 作。

select t.*from (select t.*,  (@rn := if(@s = subject, @rn + 1,  if(@s := subject, 1, 1) )  ) as rn      from t cross join(select @rn := 0, @s := '') params      order by subject, marks desc     ) t where rn <= 3order by t.subject, t.rn;