Question

我正在尝试设置一个SQL查询，以这种方式为每个用户获取具有update_at的最新值的行：

select cr.id_client,cr.updated_at,from_unixtime(cr.updated_at)
from clients_records as cr 
join clients_survey_records as csr 
on cr.id=csr.id 
group by id_client
having updated_at = max(updated_at)

但是它不起作用

Answer 1

使用corelates子查询

select c1.* from clients_records c1
where c1.updated_at=( select max(updated_at) from clients_records
                   c2 where c1.id_client=c2.id_client
                     )

Answer 2

我认为您只需要MAX()函数：

select cr.id_client, max(csr.updated_at), from_unixtime(max(csr.updated_at))
from clients_records  cr join 
     clients_survey_records csr 
     on cr.id = csr.id 
group by id_client;

Answer 3

早上好。

如果我了解您，则可以获取最新的修改过的寄存器。正确？如果是这样，请尝试：

SELECT cr.id_client, 
    (
        //Some query to concat and group data contained at clients_survey_records that You need
    ) AS last_survey_records
FROM clients_records as cr 
    INNER JOIN clients_survey_records as cs 
WHERE cr.id_client = cs.fk_client_id 
ORDER BY cr.id_client;

您可以通过updated_at轻松订购调查记录。

一些链接： https://www.w3resource.com/mysql/string-functions/mysql-concat-function.php https://www.w3resource.com/mysql/aggregate-functions-and-grouping/aggregate-functions-and-grouping-group_concat.php https://www.w3resource.com/mysql/string-functions/mysql-concat_ws-function.php

为每个客户获取最大价值

3 个答案: