Remove duplicate records based on multiple columns?

Question

I\'m using Heroku to host my Ruby on Rails application and for one reason or another, I may have some duplicate rows.

Is there a way to delete duplicate records base

Answer 1

You could try the following: (based on previous answers)

ids = Model.group('name, year, trim').pluck('MIN(id)')

to get all valid records. And then:

Model.where.not(id: ids).destroy_all

to remove the unneeded records. And certainly, you can make a migration that adds a unique index for the three columns so this is enforced at the DB level:

add_index :models, [:name, :year, :trim], unique: true