MySQL 左连接与多个计数

Question

我有这3张 table

users [ id , username, password ]
logs [ id, user_id, action ]
user_propeties [ id, user_id, prop_name, prop_value ]

我想仅根据用户 ID 从 2 个表中选择具有 Count(logs.id) 和 count(user_propeties.id) 的所有用户列，其中 prop_value 为 NULL

我有以下查询

SELECT t1.*, count(t2.`id`) as total_logs,count(t3.`id`) as total_propeties
                       FROM `users` t1
                       LEFT JOIN `user_propeties` t2
                                ON t1.`id` = t2.`user_id` AND ISNULL(t2.`prop_value`)
                       LEFT JOIN `logs` t3
                                ON t3.`user_id` = t1.`id`                                       
                       GROUP BY t1.id
                       ORDER BY t1.id DESC

返回行，但计数值错误。我做错了什么？谢谢

Answer 1

我怀疑您需要一些DISTINCT，否则它将返回日志和属性的所有组合的计数；

SELECT t1.*, COUNT(DISTINCT t2.`id`) as total_logs,
             COUNT(DISTINCT t3.`id`) as total_propeties
FROM `users` t1
LEFT JOIN `user_propeties` t2
         ON t1.`id` = t2.`user_id` AND ISNULL(t2.`prop_value`)
LEFT JOIN `logs` t3
         ON t3.`user_id` = t1.`id`                                       
GROUP BY t1.id
ORDER BY t1.id DESC