php – MySQL：查询带有关系的排行榜

我知道这是一个热门话题,但我仍然没有找到我正在寻找的东西.我想查询一个表

BOOKS_READ
id
user_id
book_id

格式化已列出最多书籍的用户的排行榜.当用户阅读书籍时,与书籍ID和用户ID匹配的记录将被记录到books_read表中.

是否可以对此查询的结果进行排名,从1开始,并考虑关系？

SELECT user_id, COUNT(*) AS book_count 
FROM books_read 
GROUP BY user_id 
ORDER BY book_count DESC LIMIT 10

如果出现平局,我想在结果中列出“=”符号.

例如,

rank  user_id  book_count  
=1    30       121
=1    17       121
 2    101      119
=3    11       104
=3    91       104

非常感谢您的帮助！我不介意使用PHP来处理其中的一些,但我对学习这些东西的直接SQL解决方案非常感兴趣:-)

解决方法:

SELECT GROUP_CONCAT(user_id, book_count
FROM (
    SELECT user_id, COUNT(*) AS book_count 
    FROM books_read 
    GROUP BY user_id 
    ORDER BY book_count DESC
) AS T1
GROUP BY book_count
ORDER BY book_count

给你

user_id  book_count  
30,17       121
101         119
11,91       104

然后,您可以使用PHP来解析关系.

<?php
$rank = 1;

while ($row = mysql_fetch_assoc($result)) {
    $users = explode(',', $row['user_id'];
    foreach ($users as $user) {
        echo 'Rank: ' . $rank . ' ' . $user . "\n;
    }
    $rank++;
}

?>

标签：php,mysql,ranking,leaderboard
来源： https://codeday.me/bug/20190630/1337667.html