Question

数据库：

player  |  team  |  points  
player1 | team1  |  100
player2 | team1  |  90
player3 | team2  |  100
player4 | team2  |  95
player5 | team2  |  90

我正在尝试从每个团队的积分中获得前2名玩家，并将他们平均分配给团队排名，同时将团队分组到查询中：

team2 97.5 (not 95)
team1 95


       `$mysqli->query("SELECT charGuild, gr FROM (
        SELECT charGuild, AVG(charRating) as gr 
        FROM ins_rated 
        GROUP BY charGuild 
        HAVING COUNT(*) >= 10
        ORDER BY gr DESC
        LIMIT 15
        )
       ORDER BY gr DESC
       LIMIT 40");`

没有按预期工作。

$mysqli->query("SELECT charGuild, AVG(charRating) AS gr 
                                        FROM ins_rated 
                                        GROUP BY charGuild 
                                        HAVING COUNT(*) >= 10
                                        ORDER BY gr DESC
                                        LIMIT 40");

列出顶级球队，他们在数据库中至少有10人。现在添加一种方法来让前15名球员仅仅平均得分球队得分就是我迷失的地方。

Answer 1

SELECT charGuild, AVG(charRating) as gr FROM ins_rated GROUP BY charGuild order by gr desc limit 2

Answer 2

错误代码：1235此版本的MySQL尚不支持'LIMIT＆amp; IN / ALL / ANY / SOME子查询'

我认为你可能需要使用一些编码。

我能做的最好的事情是：

SELECT charGuild, charRating
FROM ins_rated a
WHERE charRating = (SELECT MAX(charRating) FROM ins_rated b WHERE b.charGuild = a.charGuild)
OR charRating = (SELECT MAX(charRating) FROM ins_rated b WHERE b.charGuild = a.charGuild
    AND charRating < (SELECT MAX(charRating) FROM ins_rated c WHERE c.charGuild = a.charGuild));

输出：

charGuild     charRating   
team 1        100          
team 1        90           
team 2        100          
team 2        95

编辑：抓一点。它获得了2个最高唯一分数。如果球队中有2名球员获得100分，则不会选择（100,100）作为最高分，但是（100,95）。

Answer 3

哇噢！

SELECT charGuild, AVG(charRating) average
FROM (SELECT charRating, charGuild FROM ins_rated a ORDER BY charRating DESC LIMIT 4) top4
GROUP BY charGuild

输出：

charGuild           average  
team 1              95.0000  
team 2              97.5000

编辑：抓一点。这个假设团队数量众所周知，每个团队至少有2人。

Answer 4

我喜欢这个：它没有我其他2个答案的任何缺陷......

SELECT charGuild, AVG(charRating) average
FROM (
    SELECT
        charRating,
        charGuild,
        @num := IF(@guild = charGuild, @num + 1, 1) AS row_number,
        @guild := charGuild
    FROM ins_rated a
        ORDER BY charGuild DESC
) ordered
WHERE row_number <= 2
GROUP BY charGuild;

输出：

charGuild     average
team 1        95.0000         
team 2        97.5000

如何在MySQL中选择TOP n分组值的平均值？

4 个答案: