ExtractYear 和 ExtractMonth 在 Django 中返回 None [英] ExtractYear and ExtractMonth returning None in Django

问题描述

我正在尝试根据年、月和列值对我的数据进行分组.查询是

I am trying to do group my data on the basis of Year, Month and a Column Value. The Query is

 FeedbackData.objects.annotate(year=ExtractYear('created'), month=ExtractMonth('created')).values('year','month','start_operator_alias').annotate(dcount=Count('*')).values('year', 'month','start_operator_alias','dcount')

我得到的结果是:

<QuerySet [{'year': None, 'start_operator_alias': 7, 'dcount': 12858, 'month': None}, {'year': None, 'start_operator_alias': 2, 'dcount': 185042, 'month': None}, {'year': None, 'start_operator_alias': 5, 'dcount': 13963, 'month': None}, {'year': None, 'start_operator_alias': 3, 'dcount': 127819, 'month': None}, {'year': None, 'start_operator_alias': 0, 'dcount': 566040, 'month': None}, {'year': None, 'start_operator_alias': 6, 'dcount': 83877, 'month': None}, {'year': None, 'start_operator_alias': 1, 'dcount': 170064, 'month': None}, {'year': None, 'start_operator_alias': -1, 'dcount': 36550, 'month': None}, {'year': None, 'start_operator_alias': 4, 'dcount': 25714, 'month': None}, {'year': None, 'start_operator_alias': 8, 'dcount': 200, 'month': None}]>

如您所见，月份和年份返回为无.这可能是什么原因或我做错了什么.

As you can see the month and year are returned as None. What can be the reason for that or what am I doing wrong.

model:
class FeedbackData(models.Model):
  deviceId = models.CharField(blank=True, null=True, max_length=64, db_tablespace="indexes")
  start_cellId = models.CharField(null=True, blank=True, max_length=32)
  end_cellId = models.CharField(null=True, blank=True, max_length=32)
  start_mcc = models.CharField(null=True, blank=True, max_length=32)
  end_mcc = models.CharField(null=True, blank=True, max_length=32)
  start_mnc = models.CharField(null=True, blank=True, max_length=32)
  end_mnc = models.CharField(null=True, blank=True, max_length=32)
  start_lac = models.CharField(null=True, blank=True, max_length=32)
  end_lac = models.CharField(null=True, blank=True, max_length=32)
  start_operator_name = models.CharField(db_index=True, null=True, max_length=32, blank=True)
  start_operator_alias = models.IntegerField(db_index=True, null=True, default=-1)
  end_operator_name = models.CharField(db_index=True, null=True, max_length=32, blank=True)
  end_operator_alias = models.IntegerField(db_index=True, null=True, default=-1)
  start_signal_strength = models.CharField(null=True, blank=True, max_length=32)
  end_signal_strength = models.CharField(null=True, blank=True, max_length=32)
  average_signal_strength = models.CharField(null=True, blank=True, max_length=32)
  phone_type = models.CharField(db_index=True, null=True, blank=True, max_length=8, default='unknown')
  call_duration = models.IntegerField(db_index=True, null=True, blank=True, default=0)
  network_type = models.CharField(db_index=True, null=True, blank=True, max_length=16, default='unknown')
  start_cell_signal_strength = models.CharField(null=True, blank=True, max_length=32)
  end_cell_signal_strength = models.CharField(null=True, blank=True, max_length=32)
  device_model = models.CharField(null=True, blank=True, max_length=64)
  device_manufacturer = models.CharField(db_index=True, null=True, blank=True, max_length=64)
  os_version = models.CharField(db_index=True, null=True, blank=True, max_length=32)
  start_time_of_call = models.DateTimeField(blank=True, null=True)
  end_time_of_call = models.DateTimeField(blank=True, null=True)
  start_lon = models.FloatField(db_index=True, null=True, blank=True)
  start_lat = models.FloatField(db_index=True, null=True, blank=True)
  end_lon = models.FloatField(db_index=True, null=True, blank=True)
  end_lat = models.FloatField(db_index=True, null=True, blank=True)
  start_lon_rad = models.FloatField(db_index=True, null=True, blank=True) 
  start_lat_rad = models.FloatField(db_index=True, null=True, blank=True)
  end_lon_rad = models.FloatField(db_index=True, null=True, blank=True)
  end_lat_rad = models.FloatField(db_index=True, null=True, blank=True)
  start_cdma_lon = models.FloatField(db_index=True, null=True, blank=True)
  start_cdma_lat = models.FloatField(db_index=True, null=True, blank=True)
  end_cdma_lon = models.FloatField(db_index=True, null=True, blank=True)
  end_cdma_lat = models.FloatField(db_index=True, null=True, blank=True)
  rating_time = models.DateTimeField(blank=True, null=True)
  speed = models.FloatField(null=True, blank=True)
  altitude = models.FloatField(null=True, blank=True)
  is_dual = models.BooleanField(db_index=True, default=False)
  is_roaming = models.BooleanField(db_index=True, default=False)
  is_network_roaming = models.BooleanField(default=False)
  call_drop = models.IntegerField(db_index=True, null=True)
  rating = models.FloatField(db_index=True, null=True, blank=True)
  state_name = models.CharField(db_index=True, null=True, blank=True, max_length=255)
  additional_info = models.CharField(db_index=True, null=True, blank=True, max_length=216)
  comment = models.CharField(null=True, blank=True, max_length=512)
  in_out = models.IntegerField(db_index=True, null=True)
  created = models.DateTimeField(db_index=True, auto_now_add=True)

推荐答案

如果您没有将任何时区信息加载到 mysql 中，就会发生这种情况

This will happen if you do not have any time zone info loaded into mysql

convert_tz 返回 null

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