Django 查询中的额外 GROUP BY 子句

Posted 2023-02-23

【中文标题】Django 查询中的额外 GROUP BY 子句

【英文标题】：Extra GROUP BY clause in django query

【发布时间】：2015-07-28 23:43:26

【问题描述】：

我已经编写了这个 Django ORM 查询：

queryset = Test.objects.all() \
    .annotate_test_date() \ # similar to extract hour 
    .annotate_test_time() \ # similar to extract hour 
    .annotate(hour=Extract(F('created_on'), function='hour')) \
    .annotate(count=Count('id')) \
    .order_by() \
    .values('hour', 'count')

形成的查询结果是：

SELECT extract (hour from ("users_test"."created_on")) AS "hour",
COUNT("users_test"."id") AS "count" 
FROM "users_test" 
GROUP BY "users_test"."id", "users_test"."author_id", "users_test"."created_on", "users_test"."modified_on", "users_test"."access_point_id", "users_test"."user_id", "users_test"."invite_id", "users_test"."building_id", "users_test"."company_id", date("users_test"."created_on"), "time"("users_test"."created_on"), extract (hour from ("users_test"."created_on"))

但所需的查询是：

SELECT extract (hour from ("users_test"."created_on")) AS "hour",
COUNT("users_test"."id") AS "count" 
FROM "users_test" 
GROUP BY extract (hour from ("users_test"."created_on"))

我认为这是由于我的查询中有额外的注释字段，但这些字段是过滤所必需的。

感谢任何帮助。

提前致谢

【参考方案1】：

按此顺序尝试：

queryset = Test.objects.all() \
    .annotate(hour=Extract(F('created_on'), function='hour')) \
    .annotate(count=Count('id')) \
    .values('hour', 'count')
    .order_by()

【讨论】：

django.core.exceptions.FieldError: Cannot resolve keyword 'hour' into field.

甚至不是亲密的伙伴，这将依赖于始终唯一的 id。

我很确定这与此有关：docs.djangoproject.com/en/1.8/topics/db/aggregation/…