3个表上的Mysql左外部联接失败

问题描述

我的MysqL DB中有3个表，如下所示：

每日数据更新：

----------------------------------------------
id      date      code   user_id  followup_status
----------------------------------------------
1     08/10/2020   AD123    1          1
2     08/10/2020   AD134    2          2
3     08/10/2020   AD123    1          1
---------------------------------------------

用户：

-------------------------------------
id   first_name  user_region
------------------------------------
1     Peter      scotland
2     Susan      ireland
------------------------------------

关注状态

------------------------------------
id  followup_status
---------------------------------------
1      Paid
2     Unpaid
----------------------------------------

我需要select date,code and followup_status from daily_data_update WHERE user_id in users以及followup_status。我的查询如下：

SELECT t1.`date`,t1.`code`,t3.`followup_status`
FROM `daily_data_update` AS t1,followupstatus AS t3
LEFT OUTER JOIN users AS t2 ON t1.user_id = t2.id
WHERE t2.id IS NOT NULL
  AND t2.user_region = 'scotland'

但是查询失败，为UnkNown column 't1.user_id' in 'on clause'

查询有什么问题，我该如何解决？正在寻求帮助。

解决方法

尝试此查询：

@RestResource(urlMapping='/sg/0.1/subscription/')
    global with sharing class SubsRecord1 {

    @HttpGet
    global static void getSubsById() {
        RestRequest request = RestContext.request;
        RestResponse response =RestContext.response;
        AggregateResult result   =  [select count(id)subcount FROM ONB2__Subscription__c where ONB2__Status__c =:'Active'];
        response.statusCode = 200;
        string jsonResponse = '{"ONB2__Subscription__c":'+'"'+result.get('subcount')+'"'+'}';
        response.responseBody = Blob.valueOf(jsonResponse);
        return;
    }
}

希望这行得通！

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