Calculate Total Orders by Customer ID

This function uses Django ORM to query the database and calculate the total number of orders placed by a specific customer. It filters the orders by the customer ID, uses the `annotate` and `Sum` aggregate functions to calculate the total quantity of items in each order, and returns the first result.

Technology Stack : Django, Django ORM, filter, annotate, Sum

Code Type : Django ORM Query and Aggregation

Code Difficulty : Intermediate

                
                    
import random
from django.core.cache import cache
from django.db.models import Sum
from django.db.models.functions import Coalesce

def calculate_total_orders_by_customer(customer_id):
    """
    This function calculates the total number of orders placed by a specific customer.
    It uses Django ORM to query the database and aggregate the results.
    """
    total_orders = Order.objects.filter(customer_id=customer_id).annotate(
        total_orders=Sum('order_items__quantity')
    ).values_list('total_orders', flat=True).first()
    return total_orders