Issue: Sorting by Rating

[MoniPar]

Since I added a new model (Review) with a rating field, I have been calculating the ratings gathered from the Review Form and saving them to the Review Table. This meant that in order to be able to sort the products by their rating, I will need to save the average rating in the Product table or find out how to add a sortkey for the average rating.

[MoniPar]

I managed to sort the average rating using annotation and the Avg() function on the Review rating field. However, the reviews with no rating are showing up first when sorting is desc and vice versa.

Possible solution: Use the F() to sort null values. https://docs.djangoproject.com/en/4.2/ref/models/expressions/#:~:text=Using%20F()%20to%20sort,ordering%20depends%20on%20your%20database.

[MoniPar]

Solution: In trying to use the nulls_last = True to control the order of the NULL value,

if 'direction' in request.GET:
    direction = request.GET['direction']
     if direction == 'desc':
         sortkey = f'-{sortkey}'
products = products.order_by(sortkey)

was conflicting with the desc(nulls_last=True). Sortkey needed to be placed in the F() with desc(nulls_last=True) and then order the products by the new variable "order_logic".

order_logic = sortkey
if 'direction' in request.GET:
    direction = request.GET['direction']
    if direction == 'desc':
        order_logic = F(sortkey).desc(nulls_last=True)
    else:
        order_logic = F(sortkey).asc(nulls_first=True)
products = products.order_by(order_logic)

Tested all other sorting parameters and seems to be working ok while the reviews with no rating are not showing last in desc and first in asc.