将复杂的SQL查询转换为Rails ActiveRecord表达式

Question

I have the following SQL which I cannot seem to express using active record objects/methods in Rails.

SELECT users.*, count(followings.user_id) as expr1 FROM users 
  inner join followings on id = follows where id in (2,3,4) 
  group by followings.follows order by expr1 desc;

Obviously, [2,3,4] is replaced with any array of Ids.

This query executes no problems, and gives the results I want. But I am having great difficulty in how to go about expressing it the 'ActiveRecord' way.

How do I get my Users model to order by the number followers?

Answer 1

You can try with this query:

User.select("users.*, count(followings.user_id)").joins(:followings)
.where("users.in (?)", [2,3,4]).group_by("followings.follows")

If you are getting other errors please let me know.