mysql - 从 mysql 表中检索所有未登录的用户(SQL 查询)

Question

下面列出了 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         |
+-------------+-------------+---------------+

我想要的是选择所有尚未登录的客户(注意 v3_customer_activity 中的 login 键)。所以在这种情况下，这将是具有 customer_id: 3

的客户

我正在使用 mysql 数据库。

我试过使用以下查询:

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)

希望它能在子查询中找到的行之间进行迭代。 这导致错误告诉我子查询可能不包含多行。

长话短说

我想要的是从 v3_customer 中检索未列在表 v3_customer_activity 中的每个客户

Answer 1

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;

用v3_customer_activity左连接v3_customer表，过滤不匹配的记录。