Question

So this below has always worked for me, but now I need to remove some of the items to get true cost and true sale price. I need to remove all items from this sum that has a parent_id of nil. How can I do this without making another sql query?

def total_price
  # convert to array so it doesn't try to do sum on database directly
  items.to_a.sum(&:full_price)
end

Answer 1

You can do

items.to_a.reject{|item|item.parent_id.nil?}.sum(&:full_price)