Question

我试图在MySQL的值为1的每个客户的时间戳之后删除行。示例表：

id | timestamp | cust_ID | value 899900 | 2016-04-11 12:00:00 | 500219 | 0 899901 | 2016-04-12 16:00:00 | 500219 | 0 899902 | 2016-04-14 11:00:00 | 500219 | 1 899903 | 2016-04-15 12:00:00 | 500219 | 1 899904 | 2016-04-23 09:00:00 | 500219 | 0 899905 | 2016-05-02 19:00:00 | 500219 | 0 909901 | 2016-04-12 16:00:00 | 500230 | 0 909902 | 2016-04-14 11:00:00 | 500230 | 1 909903 | 2016-04-15 12:00:00 | 500230 | 1 909904 | 2016-04-23 09:00:00 | 500230 | 0 909905 | 2016-05-02 19:00:00 | 500230 | 0 939905 | 2016-05-02 19:00:00 | 500240 | 0

努力实现：

id | timestamp | cust_ID | value 899900 | 2016-04-11 12:00:00 | 500219 | 0 899901 | 2016-04-12 16:00:00 | 500219 | 0 899902 | 2016-04-14 11:00:00 | 500219 | 1 899903 | 2016-04-15 12:00:00 | 500219 | 1 909901 | 2016-04-12 16:00:00 | 500230 | 0 909902 | 2016-04-14 11:00:00 | 500230 | 1 909903 | 2016-04-15 12:00:00 | 500230 | 1 939905 | 2016-05-02 19:00:00 | 500240 | 0

到目前为止，我有以下内容抛出错误1242'子查询返回多行'：

CREATE VIEW max_id AS SELECT id, cust_ID, MAX(timestamp) FROM table WHERE value = 1 GROUP BY cust_ID; DELETE FROM max_id WHERE id > (SELECT id FROM max_id GROUP BY cust_ID);

非常感谢任何帮助！

Answer 1

我不是100％你想要的逻辑是什么。但是，您应该可以使用join。以下内容删除时间戳大于最大时间戳的客户的所有行，其中＆＃34; 1＆＃34;对于那个客户：

delete t
    from table t join
         (select t.cust_Id, max(timestamp) as maxts
          from table t
          group by t.cust_id
         ) tt
         on t.cust_id = tt.cust_id and tt.timestamp > t.timestamp

MySQL根据值删除行，并在每个客户的时间戳之后删除

1 个答案: