枚举postgresql

Question

有没有什么办法来枚举postgresql中的查询行？

我的表是这样的：

Table players 
id player_id game_id points 

而且我想这样的查询：

SELECT game_id, <row_number in points group>, <array of ids> 
    FROM players WHERE game_id = %s 
    GROUP BY game_id, points; 

Answer 1

我不知道你问什么。 “分组中的行号”是一个简单的window function应用程序，但我不知道“id数组”是什么意思。

给定的日期是这样的：

id | player_id | game_id | points 
----+-----------+---------+-------- 
    1 |   1 |  1 |  0 
    2 |   1 |  2 |  1 
    3 |   1 |  3 |  5 
    4 |   2 |  1 |  1 
    5 |   2 |  2 |  0 
    6 |   2 |  3 |  0 
    7 |   3 |  1 |  2 
    8 |   3 |  2 |  3 
    9 |   3 |  3 |  1 

你可以得到每场比赛的排名与此：

select game_id, player_id, points, 
     rank() over (partition by game_id order by points desc) 
from players 

这将会给喜欢这一点，你的输出：

game_id | player_id | points | rank 
---------+-----------+--------+------ 
     1 |   3 |  2 | 1 
     1 |   2 |  1 | 2 
     1 |   1 |  0 | 3 
     2 |   3 |  3 | 1 
     2 |   1 |  1 | 2 
     2 |   2 |  0 | 3 
     3 |   1 |  5 | 1 
     3 |   3 |  1 | 2 
     3 |   2 |  0 | 3 

Answer 2

这应该做你正在寻找的东西：

SELECT game_id 
, row_number() OVER (PARTITION BY game_id ORDER BY points) AS num 
, array_agg(id) AS ids 
FROM players WHERE game_id = %s 
GROUP BY game_id, points 
ORDER BY game_id, points