从Django模型中从日期时间字段中提取所有唯一年份

Question

running sqlite3 and the defulte datetime field how can I pull all unique years/months/days from the data base without iterating though all entries. Distinct does not appear to work with sqlite3, and without the slow iteration of all the dates I can not think of another way to do this.

to be clear I want to pull all unique values from the database, and not filter to them.

Answer 1

The QuerySet method datetimes handles this:

>>> SomeModel.objects.all().datetimes('date_field', 'year')
[datetime.date(2014, 1, 1), datetime.date(2015, 1, 1)]

>>> [d.year for d in SomeModel.objects.all().datetimes('date_field', 'year')]
[2014, 2015]

Updated to use datetimes for DateTimeField fields. For a DateField , use dates .