Question

我试图找到某个月的平均分数。

所以我想要一天的平均分数。一个人每天可以竞争超过1个任务，所以我想要那天的平均分数。

然后我想要这个月的平均分。

这是我想要django做的原始sql：

SELECT AVG(avg_score) as mon_avg, EXTRACT(year FROM c_date) as y, 
EXTRACT(month FROM c_date) as m
FROM ( 
   SELECT AVG(SCORE) AS avg_score, DATE(created) as c_date
   FROM companies_task
   GROUP BY c_Date 
) as DAY_AVERAGE  GROUP BY y, m
ORDER BY y, m

我的模型看起来像这样：

Task(models.Model):
    score = models.IntegerField()
    completed = models.DateTimeFiled(auto_now=True)

我目前的尝试是：

Task.objects.filter(created=year_ago())\
    .extra(select={"date": "date(created)"})\
    .values('date')\
    .annotate(avg_score=Avg('score'))\
    .extra(select={
        'year': "EXTRACT(year FROM date)",
        'month': "EXTRACT(month from date)"
    })\
    .values('year', 'month')\
    .annotate(month_avg=Avg('avg_score'))

我得到的错误是：

FieldError: Cannot resolve keyword 'year' into field. Choices are: avg_score, created, date, employee, employee_id, id, modified, month, score, year


FieldError                                Traceback (most recent call last)
/usr/local/lib/python3.4/site-packages/django/db/models/sql/query.py in add_fields(self, field_names, allow_m2m)
   1631                 _, targets, _, joins, path = self.setup_joins(
-> 1632                     name.split(LOOKUP_SEP), opts, alias, allow_many=allow_m2m)
   1633                 targets, final_alias, joins = self.trim_joins(targets, joins, path)

/usr/local/lib/python3.4/site-packages/django/db/models/sql/query.py in setup_joins(self, names, opts, alias, can_reuse, allow_many)
   1404         path, final_field, targets, rest = self.names_to_path(
-> 1405             names, opts, allow_many, fail_on_missing=True)
   1406 

/usr/local/lib/python3.4/site-packages/django/db/models/sql/query.py in names_to_path(self, names, opts, allow_many, fail_on_missing)
   1329                     raise FieldError("Cannot resolve keyword %r into field. "
-> 1330                                      "Choices are: %s" % (name, ", ".join(available)))
   1331                 break

FieldError: Cannot resolve keyword 'year' into field. Choices are: created, employee, employee_id, id, modified, score

During handling of the above exception, another exception occurred:

FieldError                                Traceback (most recent call last)
<ipython-input-12-d207d6f92a38> in <module>()
      3             'month': "EXTRACT(month from date)"
      4         })\
----> 5         .values('year', 'month')\
      6         .annotate(avg__somehthing=Avg('avg_score'))

/usr/local/lib/python3.4/site-packages/django/db/models/query.py in values(self, *fields)
    710 
    711     def values(self, *fields):
--> 712         clone = self._values(*fields)
    713         clone._iterable_class = ValuesIterable
    714         return clone

/usr/local/lib/python3.4/site-packages/django/db/models/query.py in _values(self, *fields)
    705 
    706         query.values_select = field_names
--> 707         query.add_fields(field_names, True)
    708 
    709         return clone

/usr/local/lib/python3.4/site-packages/django/db/models/sql/query.py in add_fields(self, field_names, allow_m2m)
   1645                                + list(self.annotation_select))
   1646                 raise FieldError("Cannot resolve keyword %r into field. "
-> 1647                                  "Choices are: %s" % (name, ", ".join(names)))
   1648 
   1649     def add_ordering(self, *ordering):

FieldError: Cannot resolve keyword 'year' into field. Choices are: created, date, employee, employee_id, id, modified, month, score, year

使用Django的ORM注释注释

0 个答案: