select 数据以分钟为单位的时间间隔 django orm

Question

How are you? I need some help please. I am working in Django and I need to make a query of all sales between 00:00 and 00:30 minutes, so every 30 minutes I need to see the sales. I was putting together something like this but it is not working.

sales = (
    SalesOrder
    .objects
    .annotate(Sum('subtotal'))
    .filter(created_at__time__range= ('00:00:00:00', ''))
    .filter(created_at__time = hour_now)
)

This is a SQL query that delivers the correct data.

SELECT sum(subtotal) as tot 
  FROM sales_salesorder ss 
 where extract(minute from created_at::time) between 31 and 59 and
       created_at::date = now()::date and 
       extract(hour from created_at) = extract(hour from CURRENT_TIME);

The problem is that I can't leave the sql query because I have to pass it through a for loop to return the data, that's why the most effective way is to use the ORM, that's the reason of my question.

Answer 1

The direct translation from your sql to django query is:

from django.utils import timezone

sales = (
    SalesOrder
    .objects
    .filter(created_at__minute__range=(31, 59))
    .filter(created_at__hour=timezone.now().hour)
    .filter(created_at__date=timezone.now().today())
    .count()
)

But, perhaps, a more elegant and index friendly approach is:

from django.utils import timezone
from datetime import datetime, timedelta

today = datetime.now().today()

date_from = timezone.datetime(
    today.year, today.month, today.day,
    0, 0, 0,
    tzinfo=timezone.get_current_timezone())

date_to = date_from + timedelta(minutes=30)

sales = (
    SalesOrder
    .objects
    .filter(created_at__range=(date_from, date_to))
    .count()
)

If you are looking to group by each half hour here a good answer: https://stackoverflow.com/a/61747028/842935