Django: Calculate the Sum of the column values through query

Michael Zippo

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I have a model

class ItemPrice( models.Model ):
     price = models.DecimalField ( max_digits = 8, decimal_places=2 )
     ....

I tried this to calculate the sum of price in this queryset:

items = ItemPrice.objects.all().annotate(Sum("price"))

what"s wrong in this query? or is there any other way to calculate the Sum of price column?

I know this can be done by using for loop on queryset but i need an elegant solution.

Thanks!

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Django: Calculate the Sum of the column values through query del: Questions

__del__

How can I make a time delay in Python?

5 answers

I would like to know how to put a time delay in a Python script.

2973

Answer #1

import time
time.sleep(5)   # Delays for 5 seconds. You can also use a float value.

Here is another example where something is run approximately once a minute:

import time
while True:
    print("This prints once a minute.")
    time.sleep(60) # Delay for 1 minute (60 seconds).

2973

Answer #2

You can use the sleep() function in the time module. It can take a float argument for sub-second resolution.

from time import sleep
sleep(0.1) # Time in seconds

Django: Calculate the Sum of the column values through query del: Questions

__del__

How to delete a file or folder in Python?

5 answers

How do I delete a file or folder in Python?

2639

Answer #1

os.remove() removes a file.
os.rmdir() removes an empty directory.
shutil.rmtree() deletes a directory and all its contents.

Path objects from the Python 3.4+ pathlib module also expose these instance methods:

pathlib.Path.unlink() removes a file or symbolic link.
pathlib.Path.rmdir() removes an empty directory.

We hope this article has helped you to resolve the problem. Apart from Django: Calculate the Sum of the column values through query, check other __del__-related topics.

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Olivia Lehnman

New York | 2023-03-24

Simply put and clear. Thank you for sharing. Django: Calculate the Sum of the column values through query and other issues with re Python module was always my weak point 😁. I just hope that will not emerge anymore

Davies Innsbruck

Shanghai | 2023-03-24

Thanks for explaining! I was stuck with Django: Calculate the Sum of the column values through query for some hours, finally got it done 🤗. Checked yesterday, it works!

Manuel Krasiko

Massachussetts | 2023-03-24

__del__ is always a bit confusing 😭 Django: Calculate the Sum of the column values through query is not the only problem I encountered. Will use it in my bachelor thesis