Question

我有问题。那么，我的表：

{{1}}

我想通过得分desc获得最后3行的每个级别。我试过这样：

{{1}}

但不行。你能帮我吗？ Thx提前和抱歉我的英语

Answer 1

有几种技术可以做到，一种方法是使用用户定义的变量

select id,`level`,score 
from (
  select *, 
  @rn:= if(@prev_level = `level`,@rn+1,1) as rn,
  @prev_level:= `level`
  from mytable,(select @rn:=0,@prev_level:=0)r
  order by `level`,score desc
)r
where r.rn <=3;

demo

Answer 2

SQL解决方案：

select * from table t1
WHERE 
        (
            SELECT  COUNT(*) 
            FROM    table  t
            WHERE t.level = t1.level AND 
                  t.score >= t1.score
        ) <= 3 order by t1.level, t1.score desc

SqlFiddle

Sql为每个级别获取最后3行

2 个答案: