将 postgres 原始查询转换为 Django ORM 查询并分组答案

【问题标题】：Convert postgres raw query to Django ORM query and group by将 postgres 原始查询转换为 Django ORM 查询并分组
【发布时间】：2020-07-13 15:20:00
【问题描述】：

我有一个原始 Postgresql 查询需要转换为 Django ORM 查询。

我能够在 Postgres 中执行查询并看到预期的结果。我在 postgres DB 上获得了 5 条原始查询记录。

但是当我执行 Django ORM 查询时，它没有给出预期的输出。我在 postgres 中得到了 ORM 查询的 78 个结果。

请让我知道我在 Django ORM 查询中哪里出错了。

原始 postgres 查询：

select customer_id, program_id, project_id, store_id, count(store_id) 
from public.alerts_alert where (customer_id=2 and program_id=134 and project_id=1364) 
group by customer_id, program_id, project_id, store_id

Django ORM 查询：

queryset = Alert.objects.filter(**filter_params).annotate(
            customer_name=F('customer__name'),
            program_name=F('program__name'),
            project_name=F('project__name'),
            store_count=Count('store')
        )

**filter_params 是我将在原始查询集中提供实际值的地方。

编辑1：

这是我尝试打印 queryset.query 时得到的结果。

SELECT "alerts_alert"."time_created", "alerts_alert"."time_modified", "alerts_alert"."registered_timestamp", "alerts_alert"."id", "alerts_alert"."title", "alerts_alert"."content", "alerts_alert"."alert_date", "alerts_alert"."expiration_date", "alerts_alert"."current_status_id", "alerts_alert"."customer_id", "alerts_alert"."store_id", "alerts_alert"."program_id", "alerts_alert"."project_id", "alerts_alert"."visit_id", "alerts_alert"."batch_id", COUNT("alerts_alert"."store_id") AS "store_count", "programs_program"."name" AS "program_name", "projects_project"."name" AS "project_name", "customers_account"."name" AS "customer_name" FROM "alerts_alert" INNER JOIN "projects_project" ON ("alerts_alert"."project_id" = "projects_project"."id") INNER JOIN "customers_account" ON ("alerts_alert"."customer_id" = "customers_account"."id") INNER JOIN "programs_program" ON ("alerts_alert"."program_id" = "programs_program"."id") WHERE ("alerts_alert"."expiration_date" IS NULL AND "alerts_alert"."project_id" = 1364 AND "alerts_alert"."customer_id" = 2 AND "alerts_alert"."program_id" = 134 AND "alerts_alert"."unregistered_timestamp" IS NULL) GROUP BY "alerts_alert"."id", "programs_program"."name", "projects_project"."name", "customers_account"."name"

我不知道为什么，但由于某种原因，django 查询集正在将id 列添加到group by 子句中，即使我没有指定它。

【问题讨论】：

标签： python django postgresql django-models django-orm

【解决方案1】：

怎么样：


queryset = Alert.objects.filter(**filter_params).values(
            'customer_id', 
            'program_id', 
            'project_id', 
            'store_id').annotate(
              customer_name=F('customer__name'),
              program_name=F('program__name'),
              project_name=F('project__name'),
              store_count=Count('store')
           )

【讨论】：

出于某种原因，我可以使用Sum() 而不是Count() 来实现它。