Rails best practice for getting past 10 entries in model-CodePudding

I want to get the sales from the past 10 weeks. I can do that with this method:

def past_10_sales(yw)
  past_sales = []
  year_week = yw

  10.times do
    sales = Sales.where(year_week: year_week.previous)

    past_sales << sales unless sales.empty?
    year_week = year_week.previous
  end
  past_sales.flatten
end

But now I need this method somewhere else as well and wanted to put it in the sales.rb model, but i don't know what the best practice of this would be or if there is something in Rails that makes this better? It feels wrong calling Sales.where in the sales.rb model...

Edit: year_week is a model with the current year and calendar week. So the current year_week would be 202244. Calling year_week.previous gives me 202243. I'm getting all the sales from a specific calendar week. This works fine btw.

Edit 2: I have a model sales.rb. in this model i save all the sales. it only matters in which calendar week the sales were made, the exact date does not matter so it looks something like this:

create_table "sales" do |t|
  t.datetime "created_at", null: false
  t.datetime "updated_at", null: false
  t.bigint "year_week_id"
  etc...
end

i also have a model year_week which just saves the year and the calendarweek and the id is like this: yearweek (so 202244). there are methods like def previous that return the previous year_week.

What i now want is all the sales form the past 10 weeks. so i call this:

    sales = Sales.where(year_week: year_week.previous)

    past_sales << sales unless sales.empty?
    year_week = year_week.previous

10 times because this way it gets all the sales in the past 10 weeks but it just doesn't feel right and i was wondering if/what better way there is for this.

CodePudding user response：

If you really have to work with a bigint you can do something like:

starting_week = Time.current.advance(weeks: -10).strftime("%Y%V").to_i
Sale.where(
  year_week: starting_week.. 
)

This uses ISO weeks. Otherwise use %U or %W. See DateTime#strftime. Of course using date_trunc('week', sales.created_at) or the equivilent database function would make this column reduntant unless the week isn't actually the same as the calender week its created.

CodePudding user response：

you can do it in the below way:

def past_10_sales(yw)
  year_week = yw.previous
  past_sales = Sales.where(year_week: (year_week-9..year_week.to_a))
end