如何从 2 个不同的表中计算用户排名

Question

我有一个users 表，其中包含phase1 和phase2 列，我需要计算每个阶段的用户排名并将其存储在这些字段中。

排名是根据不同的表格 points 计算的，其中我有每个用户的分阶段积分。

我想做的是

1. 按阶段对每个用户的所有分数求和，并据此计算他的排名
2. 如果用户积分相等，比较grade1的总和，如果也相等，比较grade2的总和
3. 更新users 表，用他在每个阶段的排名

这是我的新表格与一些演示数据的样子 sql fiddle demo

目前我使用下面的代码从我的旧表中计算排名，其中排名和用户信息都在同一个表中

old sql fiddle demo

update users a
join (
  select id,
  (
      select count(distinct total) 
      from users d
      where c.total < d.total
  ) +1 rank
  from users c
) b on a.id = b.id
set a.rank = b.rank

Answer 1

oracle 中有一个名为 rank() 和 dense_rank() 的分析函数，它们对获取结果很有用。

当您使用 mysql 时，我尝试将这些函数转换为 mysql 等效项。 您可以使用以下查询获得所需的结果，您可以使用它来更新用户表。如果在成绩上也有相同的逻辑，您可能需要进一步更改它。

set @pk1 ='';
set @rn1 =1;
set @tot ='';
set @val =1;


SELECT  id,
        name,
        phase,
        phasetotal,
        denseRank
FROM
(
  SELECT  id,
          name,
          phase,
          phasetotal,
          @rn1 := if(@pk1=phase, @rn1+@val,1) as denseRank,
          @val := if(@pk1=phase, if(@tot=phasetotal, @val+1, 1),1) as value,
          @pk1 := phase,
          @tot := phasetotal     
  FROM
  (
        select users.id,users.name, points.phase, sum(points.points) 
        as phasetotal from users,points where users.id = points.userid 
        group by users.id, points.phase order by points.phase, phasetotal desc, points.grade1 desc, points.grade2 desc    
) A
) B;

这里是更新查询

set @pk1 ='';
set @rn1 =1;
set @tot ='';
set @val =1;


UPDATE users u join (
SELECT  id,
        name,
        phase,
        phasetotal,
        denseRank
FROM
(
  SELECT  id,
          name,
          phase,
          phasetotal,
          @rn1 := if(@pk1=phase, @rn1+@val,1) as denseRank,
          @val := if(@pk1=phase, if(@tot=phasetotal, @val+1, 1),1) as value,
          @pk1 := phase,
          @tot := phasetotal     
  FROM
  (
        select users.id,users.name, points.phase, sum(points.points) 
        as phasetotal from users,points where users.id = points.userid 
        group by users.id, points.phase order by points.phase, phasetotal desc, points.grade1 desc, points.grade2 desc    
) A
) B ) C on u.id = C.id
   SET u.phase1 = CASE WHEN C.phase = 1 and u.phase1 = 0 THEN C.denseRank ELSE u.phase1 END,
       u.phase2 = CASE WHEN C.phase = 2 and u.phase2 = 0 THEN C.denseRank ELSE u.phase2 END;