Django：为Model.objects.filter的（注释）字段设置一个别名

Question

When group by is used on a Django Model filtering, how can we set an alias/label to the order by field in the response?

now = datetime.now()

Attendance.objects.filter(member_id=user_id, date__gte=now.date()).values('attdate__week_day').annotate(
attendance_amount=Count('attdate__week_day'))

This returns the following.

{
"attdate__week_day": 2,
"attendance_amount": 2
}

In above result set I need to change the "date__week_day" to "day". Is this possible?

Answer 1

Yes, use this:

Attendance.objects.filter(
    member_id=user_id, date__gte=now.date()
).annotate(
    day=F('date__week_day')
).values('day').annotate(
    attendance_amount=Count('day')
)

Answer 2

You can use F expression in values() directly:

Attendance.objects.filter(member_id=user_id, date__gte=now.date()).values(day=F('attdate__week_day')).annotate(
attendance_amount=Count('day'))

Or ExtractWeekDay function if you need extract only weekday:

Attendance.objects.filter(member_id=user_id, date__gte=now.date()).values(day=ExtractWeekDay('attdate')).annotate(
attendance_amount=Count('day'))