Count and Sum of fields in Django Models

Question

I have a Customer Model and an Orders Model as below

class Customer(models.Model):
    id = models.AutoField(primary_key = True)
    name = models.CharField(max_length = 100)
    city = models.CharField(max_length = 100)

class Order(models.Model):
    id = models.AutoField(primary_key = True)
    value = models.FloatField(default=0.00)      customer = models.ForeignKey(Customer, on_delete = models.SET_NULL, blank = True, null = True)

Now I want to display the following information by iterating through the lists:

1] Count of Customers from each City
2] Total value of Orders from each City
3] Count of Orders from each Customer
4] Total Sum of Orders from each Customer

The above information has to be displayed in HTML tables using {% for %}{% endfor %} loop.

I've been looking for a solution to this for a long time now. Will be a great help if you an provide me the solution.

Thanks in advance.

Answer 1

To display the required information in HTML tables using Django's template system, you can follow these steps:

1. Retrieve the data from the database:

from django.db.models import Count, Sum

# Step 1: Retrieve the data from the database

customers = Customer.objects.all().annotate(

    order_count=Count('order', distinct=True),

    order_sum=Sum('order__value')

).order_by('city')

cities = customers.values('city').annotate(

    customer_count=Count('id'),

    order_sum=Sum('order__value')

).order_by('city')

2. Pass the data to the template context:

from django.shortcuts import render # Step 2: Pass the data to the template context context = { 'cities': cities, 'customers': customers } return render(request, 'your_template.html', context)

3. Iterate over the data in the HTML template:

<!-- Step 3: Iterate over the data in the HTML template -->

<!-- Display Count of Customers from each City -->

<table>

  <thead>

    <tr>

      <th>City</th>

      <th>Customer Count</th>

    </tr>

  </thead>

  <tbody>

    {% for city in cities %}

    <tr>

      <td>{{ city.city }}</td>

      <td>{{ city.customer_count }}</td>

    </tr>

    {% endfor %}

  </tbody>

</table>

<!-- Display Total value of Orders from each City -->

<table>

  <thead>

    <tr>

      <th>City</th>

      <th>Order Value Sum</th>

    </tr>

  </thead>

  <tbody>

    {% for city in cities %}

    <tr>

      <td>{{ city.city }}</td>

      <td>{{ city.order_sum }}</td>

    </tr>

    {% endfor %}

  </tbody>

</table>

<!-- Display Count of Orders from each Customer -->

<table>

  <thead>

    <tr>

      <th>Customer</th>

      <th>Order Count</th>

    </tr>

  </thead>

  <tbody>

    {% for customer in customers %}

    <tr>

      <td>{{ customer.name }}</td>

      <td>{{ customer.order_count }}</td>

    </tr>

    {% endfor %}

  </tbody>

</table>

<!-- Display Total Sum of Orders from each Customer -->

<table>

  <thead>

    <tr>

      <th>Customer</th>

      <th>Order Sum</th>

    </tr>

  </thead>

  <tbody>

    {% for customer in customers %}

    <tr>

      <td>{{ customer.name }}</td>

      <td>{{ customer.order_sum }}</td>

    </tr>

    {% endfor %}

  </tbody>

</table>

Make sure to replace 'your_template.html' with the actual template file name where you want to display this data.

Answer 2

To display the desired information in HTML tables using Django's template system, you can follow these steps:

1. Retrieve the necessary data from the database, including the count of customers from each city and the total value of orders from each city. Additionally, annotate the customers with the count of orders and the total sum of orders for each customer. Order the data by city.
2. Pass the retrieved data to the template context.
3. In the HTML template, use a {% for %} loop to iterate over the data and generate the HTML tables.
   • For the count of customers from each city, create a table displaying the city and the corresponding customer count.
   • For the total value of orders from each city, create a table showing the city and the order value sum.
   • For the count of orders from each customer, create a table presenting the customer's name and the order count.
   • For the total sum of orders from each customer, create a table displaying the customer's name and the order sum.

Ensure that you replace 'your_template.html' with the actual name of your template file where you want to display the information.

Answer 3

To generate HTML tables using Django's template system and display the required information, you can follow these steps:

1. Fetch the necessary data from the database by retrieving the count of customers from each city and the total value of orders from each city. Additionally, annotate the customers with the count of orders and the total sum of orders for each customer. Ensure that the data is ordered by city.
2. Pass the obtained data to the template context.
3. Within the HTML template, utilize the {% for %} loop to iterate over the data and construct the HTML tables accordingly.
   • For the count of customers from each city, create a table that presents the city and the corresponding count of customers.
   • For the total value of orders from each city, create a table that displays the city and the sum of order values.
   • For the count of orders from each customer, create a table that showcases the customer's name and the count of their orders.
   • For the total sum of orders from each customer, create a table that exhibits the customer's name and the sum of their orders.

Remember to replace 'your_template.html' with the actual filename of your template where you wish to showcase the information.