检索所有没有登录用户从MySQL表（SQL查询）

Question

我有如下2个表：

+-------------+-----------+--------------+-------------------------------+ 
|        v3_customer        | 
+-------------+-----------+--------------+-------------------------------+ 
| customer_id | firstname | lastname |    email    | 
+-------------+-----------+--------------+-------------------------------+ 
|   1 | Piet  | Pizza  | piet.pizza@example.com  | 
|   2 | Klaas  | Hein   | klaas.hein@example.com  | 
|   3 | Henk  | Crowdcontrol | henk.crowdcontrol@example.com | 
+-------------+-----------+--------------+-------------------------------+ 

+-------------+-------------+---------------+ 
|   v3_customer_activity   | 
+-------------+-------------+---------------+ 
| activity_id | customer_id |  key  | 
+-------------+-------------+---------------+ 
|   1 |   1 | login   | 
|   2 |   1 | order_account | 
|   3 |   2 | login   | 
+-------------+-------------+---------------+ 

我要的是选择已经没有登录的所有客户（注意登录键v3_customer_activity）。所以在这种情况下，这将是客户customer_id：3

我正在使用mysql数据库。

我曾尝试使用下面的查询尝试：

SELECT DISTINCT v3_customer.customer_id, v3_customer.firstname, v3_customer.lastname, v3_customer.email FROM `v3_customer` JOIN v3_customer_activity ON v3_customer.customer_id = v3_customer_activity.customer_id WHERE v3_customer.customer_id != (SELECT v3_customer_activity.customer_id FROM v3_customer_activity) 

在此希望它会在子查询中发现的行之间循环。 这导致了一个错误，告诉我一个子查询可能不包含多行。

TL; DR

我想要的是检索v3_customer每一个客户谁不是在表v3_customer_activity

Answer 1

上市试试这个：

select v3_customer.* from v3_customer 
left join v3_customer_activity on v3_customer.customer_id=v3_customer_activity.customer_id 
where v3_customer_activity.customer_id is null; 

LEFT JOIN v3_customer表v3_customer_activity和不匹配的过滤器记录。

Answer 2

select v3_customer.* from v3_customer 
where v3_customer.customer_id not in (SELECT v3_customer_activity.customer_id FROM v3_customer_activity)