複雜的MySQL排名查詢與領帶

Question

比方說，我在下面的表格有：

id | name | points 
------------------- 
1 | joe | 100 
2 | bob | 95 
3 | max | 95 
4 | leo | 90 

我能產生相反的排名記錄，像這樣：

id | name | points | rank 
-------------------------- 
4 | leo | 90  | 1 
3 | max | 95  | 2.5 
2 | bob | 95  | 2.5 
1 | joe | 100 | 4 

Answer 1

這是一個完全工作的例子，這個示例表

create table tpoints (id int, name varchar(10), points int); 
insert tpoints values 
(1 ,'joe', 100), 
(2 ,'bob', 95 ), 
(3 ,'max', 95 ), 
(4 ,'leo', 90 ); 

MySQL查詢

select t.*, sq.`rank` 
from 
(
    select 
     points, 
     @rank := case when @g = points then @rank else @rn + (c-1)/2.0 end `rank`, 
     @g := points, 
     @rn := @rn + c 
    from 
     (select @g:=null, @rn:=1) g, 
     (select points, count(*) c 
     from tpoints 
     group by points 
     order by points asc) p 
) sq inner join tpoints t on t.points = sq.points 
order by t.points asc; 

它也有表現很好相比，執行相關的雜交（自交）的利益聯結。

• 1X穿過tpoints聚集成團
• 與領帶
• 1X加入到表把隊伍對記錄計算排名。

Answer 2

不會做「2.5」作爲等級值，但重複將具有相同的號碼，如果你使用：

SELECT x.id, 
     x.name, 
     x.points, 
     (SELECT COUNT(*) 
      FROM YOUR_TABLE y 
      WHERE y.points <= x.points) AS rank 
    FROM YOUR_TABLE x 
ORDER BY x.points