Nalutas: Ibalik ang buwanang halaga ng benta sa Django

Ang pangunahing problema na nauugnay sa pagbabalik ng buwanang halaga ng benta sa Django ay maaaring mahirap itong kalkulahin.

I have a Django project with a model that looks like this:
<code>class Sales(models.Model):
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    quantity = models.IntegerField()
    date = models.DateField()

    def __str__(self):
        return str(self.product)
</code>
I need to write a view that returns the total sales value for each month in JSON format, something like this: 
<code>[{"month": 1, "total": 100}, {"month": 2, "total": 200}]</code>


A:


You can use <code>annotate</code> and <code>values</code>:  https://docs.djangoproject.com/en/2.1/ref/models/querysets/#values  (also see https://docs.djangoproject.com/en/2.1/ref/models/querysets/#annotate )   This will give you a queryset of dictionaries with the keys you want and the values you want (the aggregated total).   Then just serialize it to json using whatever method you prefer (https://docs.djangoproject.com/en/2.1/_modules/django/core/serializers/) .  I would recommend using django-rest-framework for this as it makes it very easy to serialize querysets into json responses: https://www.django-rest-framework.org/.   If you don't want to use rest framework then look at how they do it here: https://github.com/tomchristie//blob//master//rest_framework//renderers//json_renderer//py#L39 .   Basically they just call <code>.dumps()</code> on your queryset after converting it into a list of dictionaries first which is what we are going to do below...     The query below should give you what you are looking for...     I'm assuming your model is called Sales and that there is also an importable module called Sales in your project somewhere so I am aliasing one of them so as not to cause confusion...     Also note that if your database is postgres then there is an aggregate function called date_trunc which will make this query much simpler but unfortunately sqlite does not support date truncation so we have to do some extra work...      Good luck!  Let me know if anything isn't clear or if there are any errors in my code below! 🙂       Cheers! -Dan Meehan       PS - In case anyone else comes across this question later on who wants the same thing but with days instead of months then here's how I would do that using sqlite3 since postgres supports date truncation out of the box...      PS - In case anyone else comes across this question later on who wants the same thing but with days instead of months then here's how I would do that using sqlite3 since postgres supports date truncation out of the box...      PS - In case anyone else comes across this question later on who wants the same thing but with days instead of months then here's how I would do that using sqlite3 since postgres supports date truncation out of the box...      PS - In case anyone else comes across this question later on who wants the same thing but with days instead of months then here's how I would do that using sqlite3 since postgres supports date truncation out of the box....     from datetime import datetime from django import db from django import forms from django import http from django import template from django import urls from django import utils #from .models import Sales as SalesModel #import Sales #SalesModule class MonthForm(forms.<strong><em></em></strong><strong><em></em></strong><strong><em></em></strong><strong><em></em></strong>)<br/> form = MonthForm() context['form'] = form return render(request, 'sales_by_month', context)</p>
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 1 mula datetime import datetime 2 3 4 

5

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Mga solusyon sa Django

Mayroong maraming mga solusyon sa Django doon. Narito ang ilan:

1. Gumamit ng isang third-party na library para gawin ang ilan sa mga mabibigat na bagay para sa iyo. Mayroong maraming magagandang Django library na magagamit, kabilang ang django-rest-framework at django-admin-tools.

2. Gumamit ng prebuilt na solusyon mula sa isang panlabas na provider. Mayroong maraming mga prebuilt na solusyon sa Django na magagamit, kabilang ang django-commerce ng Bigcommerce at django-shopify-storefront ng Shopify.

3. Bumuo ng sarili mong solusyon mula sa simula gamit ang Django at ang naaangkop na mga aklatan. Maaari itong maging isang masayang proyekto kung mayroon kang karanasan sa programming, o maaari itong maging mas mahirap kung wala kang anumang karanasan sa pag-coding sa Python.

Mga balangkas ng Django

Mayroong maraming mga Django framework na magagamit, ngunit ang pinakasikat ay ang Django REST Framework at Django Model View Controller (MVC).

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