'Rails sum all prices inside a record

I have a model Products that belongs_to model Kit

Kit has_many Products

¿How can I sum all of the prices of each product that belongs to a kit?

I tried with no luck:

@kitprice = Kit.products.price.sum
ruby-on-rails


Solution 1:[1]

Try this:

@kitprice = kit.products.sum(:price)

In my case i have wallet with many operations

wallet = Wallet.first
amount = wallet.operations.sum(:amount)

Solution 2:[2]

Question is slightly ambiguous. Assuming you have an instance of Kit named as kit, and a kit has many product objects; following would get you the desired result.

sum = 0
kit_id = <enter kit id here>
kit = Kit.find_by_id(kit_id)

# iterate through every product object and compound price here
kit.products.each{|product| sum = sum + product.price} 

puts sum

Basically you need to iterate through every product object and compute the sum, since it's a has many relationship.

Solution 3:[3]

This will give you every kit with the sum of it's products, i assume there is a column named name in your kit model

@kit_products_price = Kit.includes(:products).group(:name).sum('products.price')

If you want the sum of all the kit products :

@kit_price = Kit.includes(:products).sum('products.price')

Solution 4:[4]

The following should work I believe:

Active Record collection

@total = kit.products.sum("price")

Ruby array

@total = kit.products.sum(&:price)

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Vasanth Saminathan
Solution 3 Bouaik Lhoussaine
Solution 4 Bright Mensah

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