Django动态计算平均值

# models.py
from django.db import models

class Order(models.Model):
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    created_at = models.DateTimeField(auto_now_add=True)

# views.py
from django.db.models import Avg
from django.http import JsonResponse
from .models import Order

def average_order_amount(request):
    avg_amount = Order.objects.aggregate(Avg('amount'))['amount__avg']
    return JsonResponse({'average_order_amount': avg_amount})

from decimal import Decimal

avg_amount = Order.objects.aggregate(Avg('amount'))['amount__avg']
avg_amount = Decimal(avg_amount).quantize(Decimal('0.01'))

# 使用索引优化查询
Order.objects.create_index([('amount',)])

# 分批计算平均值
from django.db.models import Avg

def batch_average_order_amount(request):
    batch_size = 1000
    orders = Order.objects.all()
    total_amount = 0
    count = 0

    for order in orders.iterator(chunk_size=batch_size):
        total_amount += order.amount
        count += 1

    avg_amount = total_amount / count if count else 0
    return JsonResponse({'average_order_amount': avg_amount})