Rails custom alphabetical sort-CodePudding

I wanted to sort the query alphabetically, but in a custom order

User
  .includes(:teachers)
  .sort_by(&:location)

Location is a code example A, B, C, D

But I want to sort location in A, D, C, B.

CodePudding user response：

If your sort order is arbitrary like in your example (A, D, C, B), you'll have to define it somewhere.

LOCATION_ORDER = {
  'A' => 0,
  'D' => 1,
  'C' => 2,
  'B' => 3,
}

Then, you can sort by that.

User
  .includes(:teachers)
  .sort_by { |u| LOCATION_ORDER[u.location] }

It's worth noting that sort_by will perform the sort in your Ruby application, not the database, but since you're using sort_by already, I'll assume that's OK with you.

CodePudding user response：

Ruby on Rails 7.0 introduced the ActiveRecord::QueryMethods#in_order_of method that allows doing these kinds of custom ordering in the database like this:

User
  .includes(:teachers)
  .in_order_of(location: [A, D, C, B])

The [A, D, C, B] array has to be replaced with useful objects, for example, a list of location names when the location attribute has the datatype string.