ruby-on-rails postgresql rails-activerecord pg

how to make NaN value as the lowest when ordering Active Record objects?

I want to sort my table but it have NaN value in it,

the problem is in ruby/rails NaN is considered as highest and I want to make it as lowest instead?

I'm thinking about removing the NaN from the list ordering the non NaN list and adding the NaN's after that

anyone have more convenience approach?

my databse is postgresql and the column type is Decimal/BigDecimal and the values is Decimal/BigDecimal

the schema is

create_table "download_speeds", force: :cascade do |t|
    t.bigint "location_id", null: false
    t.string "operator_name"
    t.decimal "avg"
    t.decimal "min"
    t.decimal "max"
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
    t.index ["location_id"], name: "index_download_speeds_on_location_id"
  end

and I want to sort/give rank to the downloads_speeds based on avg column descendingly

highest avg is on top (rank 1)

Solution

apparently it is just the way postgresql ordering with NaN

the workaround for this is using SQL syntax to change the NaN into null then set an options to set the null value to be the last when ordering

 DownloadSpeed.order(Arel.sql("nullif(avg, 'NaN') desc nulls last"))